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Ошибка valueerror invalid literal for int with base 10

I got this error from my code:

ValueError: invalid literal for int() with base 10: ''.

What does it mean? Why does it occur, and how can I fix it?

Karl Knechtel's user avatar

Karl Knechtel

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asked Dec 3, 2009 at 17:34

Sarah Cox's user avatar

2

The error message means that the string provided to int could not be parsed as an integer. The part at the end, after the :, shows the string that was provided.

In the case described in the question, the input was an empty string, written as ''.

Here is another example — a string that represents a floating-point value cannot be converted directly with int:

>>> int('55063.000000')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: invalid literal for int() with base 10: '55063.000000'

Instead, convert to float first:

>>> int(float('55063.000000'))
55063

Karl Knechtel's user avatar

Karl Knechtel

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answered Jan 20, 2012 at 21:49

FdoBad's user avatar

FdoBadFdoBad

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9

The following work fine in Python:

>>> int('5') # passing the string representation of an integer to `int`
5
>>> float('5.0') # passing the string representation of a float to `float`
5.0
>>> float('5') # passing the string representation of an integer to `float`
5.0
>>> int(5.0) # passing a float to `int`
5
>>> float(5) # passing an integer to `float`
5.0

However, passing the string representation of a float, or any other string that does not represent an integer (including, for example, an empty string like '') will cause a ValueError:

>>> int('')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: invalid literal for int() with base 10: ''
>>> int('5.0')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: invalid literal for int() with base 10: '5.0'

To convert the string representation of a floating-point number to integer, it will work to convert to a float first, then to an integer (as explained in @katyhuff’s comment on the question):

>>> int(float('5.0'))
5

Karl Knechtel's user avatar

Karl Knechtel

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answered Dec 12, 2017 at 2:26

Peter's user avatar

PeterPeter

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int cannot convert an empty string to an integer. If the input string could be empty, consider either checking for this case:

if data:
    as_int = int(data)
else:
    # do something else

or using exception handling:

try:
    as_int = int(data)
except ValueError:
    # do something else

Karl Knechtel's user avatar

Karl Knechtel

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answered Dec 3, 2009 at 17:40

SilentGhost's user avatar

SilentGhostSilentGhost

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5

Python will convert the number to a float. Simply calling float first then converting that to an int will work:
output = int(float(input))

Karl Knechtel's user avatar

Karl Knechtel

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answered Apr 23, 2019 at 3:21

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Brad123Brad123

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1

This error occurs when trying to convert an empty string to an integer:

>>> int(5)
5
>>> int('5')
5
>>> int('')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: invalid literal for int() with base 10: ''

Karl Knechtel's user avatar

Karl Knechtel

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answered Mar 27, 2018 at 6:59

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JoishJoish

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The reason is that you are getting an empty string or a string as an argument into int. Check if it is empty or it contains alpha characters. If it contains characters, then simply ignore that part.

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answered Jun 23, 2017 at 13:19

rajender kumar's user avatar

1

Given floatInString = '5.0', that value can be converted to int like so:

floatInInt = int(float(floatInString))

Karl Knechtel's user avatar

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answered Dec 13, 2019 at 11:12

Hrvoje's user avatar

HrvojeHrvoje

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You’ve got a problem with this line:

while file_to_read != " ":

This does not find an empty string. It finds a string consisting of one space. Presumably this is not what you are looking for.

Listen to everyone else’s advice. This is not very idiomatic python code, and would be much clearer if you iterate over the file directly, but I think this problem is worth noting as well.

answered Dec 3, 2009 at 17:56

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1

I recently came across a case where none of these answers worked. I encountered CSV data where there were null bytes mixed in with the data, and those null bytes did not get stripped. So, my numeric string, after stripping, consisted of bytes like this:

x00x31x00x0dx00

To counter this, I did:

countStr = fields[3].replace('x00', '').strip()
count = int(countStr)

…where fields is a list of csv values resulting from splitting the line.

answered Jan 10, 2020 at 17:42

T. Reed's user avatar

T. ReedT. Reed

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My simple workaround to this problem was wrap my code in an if statement, taking advantage of the fact that an empty string is not «truthy»:

Given either of these two inputs:

input_string = ""    # works with an empty string
input_string = "25"  # or a number inside a string

You can safely handle a blank string using this check:

if input_string:
   number = int(input_string)
else:
   number = None # (or number = 0 if you prefer)

print(number)

answered Jan 3, 2022 at 0:30

Allen Ellis's user avatar

1

This could also happen when you have to map space separated integers to a list but you enter the integers line by line using the .input().
Like for example I was solving this problem on HackerRank Bon-Appetit, and the got the following error while compiling
enter image description here

So instead of giving input to the program line by line try to map the space separated integers into a list using the map() method.

answered Nov 28, 2017 at 6:32

Amit Kumar's user avatar

Amit KumarAmit Kumar

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1

your answer is throwing errors because of this line

readings = int(readings)
  1. Here you are trying to convert a string into int type which is not base-10. you can convert a string into int only if it is base-10 otherwise it will throw ValueError, stating invalid literal for int() with base 10.

answered May 28, 2020 at 21:10

shubham's user avatar

This seems like readings is sometimes an empty string and obviously an error crops up.
You can add an extra check to your while loop before the int(readings) command like:

while readings != 0 or readings != '':
    readings = int(readings)

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OneCricketeer

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answered Feb 12, 2020 at 5:07

Kanishk Mair's user avatar

Kanishk MairKanishk Mair

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I am creating a program that reads a
file and if the first line of the file
is not blank, it reads the next four
lines. Calculations are performed on
those lines and then the next line is
read.

Something like this should work:

for line in infile:
    next_lines = []
    if line.strip():
        for i in xrange(4):
            try:
                next_lines.append(infile.next())
            except StopIteration:
                break
    # Do your calculation with "4 lines" here

answered Dec 3, 2009 at 17:49

Imran's user avatar

ImranImran

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Another answer in case all of the above solutions are not working for you.

My original error was similar to OP: ValueError: invalid literal for int() with base 10: ‘52,002’

I then tried the accepted answer and got this error: ValueError: could not convert string to float: ‘52,002’ —this was when I tried the int(float(variable_name))

My solution is to convert the string to a float and leave it there. I just needed to check to see if the string was a numeric value so I can handle it correctly.

try: 
   float(variable_name)
except ValueError:
   print("The value you entered was not a number, please enter a different number")

Dharman's user avatar

Dharman

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answered Jun 25, 2021 at 14:17

justanotherdev2's user avatar

1

На чтение 7 мин Просмотров 40к. Опубликовано 17.06.2021

В этой статье мы рассмотрим из-за чего возникает ошибка ValueError: Invalid Literal For int() With Base 10 и как ее исправить в Python.

Содержание

  1. Введение
  2. Описание ошибки ValueError
  3. Использование функции int()
  4. Причины возникновения ошибки
  5. Случай №1
  6. Случай №2
  7. Случай №3
  8. Как избежать ошибки?
  9. Заключение

Введение

ValueError: invalid literal for int() with base 10 — это исключение, которое может возникнуть, когда мы пытаемся преобразовать строковый литерал в целое число с помощью метода int(), а строковый литерал содержит символы, отличные от цифр. В этой статье мы попытаемся понять причины этого исключения и рассмотрим различные методы, позволяющие избежать его в наших программах.

Описание ошибки ValueError

ValueError — это исключение в Python, которое возникает, когда в метод или функцию передается аргумент с правильным типом, но неправильным значением. Первая часть сообщения, т.е. «ValueError», говорит нам о том, что возникло исключение, поскольку в качестве аргумента функции int() передано неправильное значение. Вторая часть сообщения «invalid literal for int() with base 10» говорит нам о том, что мы пытались преобразовать входные данные в целое число, но входные данные содержат символы, отличные от цифр в десятичной системе счисления.

Использование функции int()

Функция int() в Python принимает строку или число в качестве первого аргумента и необязательный аргумент base, обозначающий формат числа. По умолчанию base имеет значение 10, которое используется для десятичных чисел, но мы можем передать другое значение base, например 2 для двоичных чисел или 16 для шестнадцатеричных. В этой статье мы будем использовать функцию int() только с первым аргументом, и значение по умолчанию для base всегда будет равно нулю. Это можно увидеть в следующих примерах.

Мы можем преобразовать число с плавающей точкой в целое число, как показано в следующем примере. Когда мы преобразуем число с плавающей точкой в целое число с помощью функции int(), цифры после десятичной дроби отбрасываются из числа на выходе.

num = 22.03
print(f"Число с плавающей точкой: {num}")
num = int(num)
print(f"Целое число: {num}")

Вывод программы:

Число с плавающей точкой: 22.03
Целое число: 22

Мы можем преобразовать строку, состоящую из цифр, в целое число, как показано в следующем примере. Здесь входные данные состоят только из цифр, поэтому они будут преобразованы в целое число.

num = "22"
print(f"Строка: {num}")
num = int(num)
print(f"Целое число: {num}")

Вывод программы

Строка: 22
Целое число: 22

Два типа входных данных, показанные в двух вышеприведенных примерах, являются единственными типами входных данных, для которых функция int() работает правильно. При передаче в качестве аргументов функции int() других типов входных данных будет сгенерирован ValueError с сообщением «invalid literal for int() with base 10». Теперь мы рассмотрим различные типы входных данных, для которых в функции int() может быть сгенерирован ValueError.

Причины возникновения ошибки

Как говорилось выше, «ValueError: invalid literal for int()» может возникнуть, когда в функцию int() передается ввод с несоответствующим значением. Это может произойти в следующих случаях.

Случай №1

Python ValueError: invalid literal for int() with base 10 возникает, когда входные данные для метода int() являются буквенно-цифровыми, а не числовыми, и поэтому входные данные не могут быть преобразованы в целое число. Это можно понять на следующем примере.

В этом примере мы передаем в функцию int() строку, содержащую буквенно-цифровые символы, из-за чего возникает ValueError, выводящий на экран сообщение «ValueError: invalid literal for int() with base 10».

num = "22я"
print(f"Строка: {num}")
num = int(num)
print(f"Целое число: {num}")

Вывод программы

Строка: 22я
Traceback (most recent call last):
  File "/Users/krnlnx/Projects/Test/num.py", line 3, in <module>
    num = int(num)
ValueError: invalid literal for int() with base 10: '22я'

Случай №2

Python ValueError: invalid literal for int() with base 10 возникает, когда входные данные функции int() содержат пробельные символы, и поэтому входные данные не могут быть преобразованы в целое число. Это можно понять на следующем примере.

В этом примере мы передаем в функцию int() строку, содержащую пробел, из-за чего возникает ValueError, выводящий на экран сообщение «ValueError: invalid literal for int() with base 10».

num = "22 11"
print(f"Строка: {num}")
num = int(num)
print(f"Целое число: {num}")

Вывод программы

Строка: 22 11
Traceback (most recent call last):
  File "/Users/krnlnx/Projects/Test/num.py", line 3, in <module>
    num = int(num)
ValueError: invalid literal for int() with base 10: '22 11'

Случай №3

Python ValueError: invalid literal for int() with base 10 возникает, когда вход в функцию int() содержит какие-либо знаки препинания, такие как точка «.» или запятая «,». Поэтому входные данные не могут быть преобразованы в целое число. Это можно понять на следующем примере.

В этом примере мы передаем в функцию int() строку, содержащую символ точки «.», из-за чего возникает ValueError, выводящий сообщение «ValueError: invalid literal for int() with base 10».

num = "22.11"
print(f"Строка: {num}")
num = int(num)
print(f"Целое число: {num}")

Вывод программы

Строка: 22.11
Traceback (most recent call last):
  File "/Users/krnlnx/Projects/Test/num.py", line 3, in <module>
    num = int(num)
ValueError: invalid literal for int() with base 10: '22.11'

Как избежать ошибки?

Мы можем избежать исключения ValueError: invalid literal for int() with base 10, используя упреждающие меры для проверки того, состоит ли входной сигнал, передаваемый функции int(), только из цифр или нет. Для проверки того, состоит ли входной сигнал, передаваемый функции int(), только из цифр, можно использовать следующие способы.

  • Мы можем использовать регулярные выражения, чтобы проверить, состоит ли входной сигнал, передаваемый функции int(), только из цифр или нет. Если входные данные содержат символы, отличные от цифр, мы можем сообщить пользователю, что входные данные не могут быть преобразованы в целое число. В противном случае мы можем продолжить работу в обычном режиме.
  • Мы также можем использовать метод isdigit(), чтобы проверить, состоит ли входная строка только из цифр или нет. Метод isdigit() принимает на вход строку и возвращает True, если входная строка, переданная ему в качестве аргумента, состоит только из цифр в десятичной системе. В противном случае он возвращает False. После проверки того, состоит ли входная строка только из цифр или нет, мы можем преобразовать входные данные в целые числа.
  • Возможна ситуация, когда входная строка содержит число с плавающей точкой и имеет символ точки «.» между цифрами. Для преобразования таких входных данных в целые числа с помощью функции int() сначала проверим, содержит ли входная строка число с плавающей точкой, т.е. имеет ли она только один символ точки между цифрами или нет, используя регулярные выражения. Если да, то сначала преобразуем входные данные в число с плавающей точкой, которое можно передать функции int(), а затем выведем результат. В противном случае будет сообщено, что входные данные не могут быть преобразованы в целое число.
  • Мы также можем использовать обработку исключений, используя try except для обработки ValueError при возникновении ошибки. В блоке try мы обычно выполняем код. Когда произойдет ошибка ValueError, она будет поднята в блоке try и обработана блоком except, а пользователю будет показано соответствующее сообщение.

Заключение

В этой статье мы рассмотрели, почему в Python возникает ошибка «ValueError: invalid literal for int() with base 10», разобрались в причинах и механизме ее возникновения. Мы также увидели, что этой ошибки можно избежать, предварительно проверив, состоит ли вход в функцию int() только из цифр или нет, используя различные методы, такие как регулярные выражения и встроенные функции.

Python is a special language which allows you to handle errors and exceptions very well. With thousands of known exceptions and ability to handle each of them, all the errors are easily removable from the code. Keeping this in mind, we’ll discuss about the invalid literal for int() error in python.

Invalid literal for int() with base 10 is caused when you try to convert an invalid object into an integer. In Python, the int() function accepts an object and then converts it to an integer provided that it is in a readable format. So, when you try to convert a string with no integers in it, it’ll throw an error. This error belongs to the ValueError category as the value of the parameter is invalid.

ValueError in Python occurs when we one passes an inappropriate argument type. Invalid literal for int() with base 10 error is caused by passing an incorrect argument to the int() function. A ValueError is raised when we pass any string representation other than that of int.

Let us understand it in detail!

ValueError: invalid literal for int() with base 10

This error message informs that there is an invalid literal for an integer in base 10. This error means that the value that we have passed cannot be converted.

Let us consider an example:

Invalid literal for int() with base 10  example
Output

It may happen that we can think that while executing the above code, the decimal part,i.e, ‘.9’ will be truncated giving the output 1. However, this does not happen as the int( ) function uses the decimal number system as its base for conversion. This means that the default base for the conversion is 10. In the decimal number system, we have numbers from 0 to 9. Thus, int() with base = 10 can only convert a string representation of int and not floats or chars.

Let us see a few examples where this error can occur:

Example 1:

example 1

In this example the value “pythonpool” is a string value passed to the int() method which gives rise to the error.

Example 2:

example 2

As the value we have used here is float inside string, this gives rise to invalid literal for int() error.

Example 3:

example 3 Invalid literal for int() with base 10

We get error in this example as we have used list inside string.

Example 4:

invalid literal example 4

The error invalid literal for int() arises because we have used tuple inside string.

Example 5:

dictionary inside string which gives rise to the error

Here, we have used dictionary inside string which gives rise to the error.

Example 6:

invalid literal for int() with base 10 example 6

The error arises in this code as we have used the empty string in the int() method.

Resolution to the Error: invalid literal for int() with base 10:

Using float to avoid decimal numbers:

1

Here, we first converted the string representation into float using the float() method. We then used the int() method to convert it into an integer.

using try-catch: to resolve invalid literal for int() with base 10

try:
    x=int("12.1")
except:
    print("Error in converting to string")
Error in converting to string

Here we have used the try-catch method to rid the invalid literal for int() with base 10 error. Basically, if the error occurs inside the try block, it is caught in the catch block, thus preventing the error.

Using isdigit():

x="12"
if x.isdigit():
    x=int(x)
    print(type(x))
<class ' int '>

In this method, we first make sure that the content inside the string is integer using the isdigit() method. As a result, the error does not occur.

Using isnumeric():

x="12"
if x.isnumeric():
    x=int(x)
    print(type(x))
<class ' int '>

Isnumeric method of the string returns the boolean stating if the string is a number. If the string contains a number then we’ll convert it to int, else not.

Conclusion:

With this, we come to an end to this article. This was an easy way to get rid of the value error in Python. If the above method does not work, then one must if the string and make sure that it does not contain any letter.

However, if you have any doubts or questions, do let me know in the comment section below. I will try to help you as soon as possible.

Happy Pythoning!

The python ValueError: Invalid literal for int() with base 10: ” error occurs when the built-in int() function is called with a string argument which cannot be parsed as an integer. The int() function returns an integer object created from a string or number. If there are no arguments, it returns 0. If the string or number can not convert as an integer, the error ValueError: Invalid literal for int() with base 10: ” will be thrown.

The int() function converts the given string or number to an integer. The default base for the int() buit-in function is 10. The digits are supposed to be between 0 and 9. The integer can also have negative numbers. If the string is empty or contains a value other than an integer, or if the string contains a float, the error ValueError: Invalid literal for int() with base 10: will be thrown.

The int() function converts the string to an integer if the string is a valid representation of the integer and validates against the base value if specified (default is base 10). The int() build in function displays the error message that shows you the exact string you were trying to parse as an integer.

Exception

The error ValueError: Invalid literal for int() with base 10: will be shown as below the stack trace. The stack trace shows the line that the int() build in function fails to parse to convert an integer from a string or a number.

Traceback (most recent call last):
  File "/Users/python/Desktop/test.py", line 1, in <module>
    print int('')
ValueError: invalid literal for int() with base 10: ''
[Finished in 0.1s with exit code 1]

How to reproduce this error

If the build in int() function is called with a string argument that contains an empty string, or contains a value other than an integer, or contains a float value, this error can be reproduced. In the example below, an attempt is made to pass an empty string to the build in int() function. The error ValueError: Invalid literal for int() with base 10: will be thrown as an empty string that can not be converted to an integer.

x=''
print int(x)

Output

Traceback (most recent call last):
  File "/Users/python/Desktop/test.py", line 1, in <module>
    print int('')
ValueError: invalid literal for int() with base 10: ''
[Finished in 0.1s with exit code 1]

Root Cause

If the build in int() function is called with a string argument that contains an empty string, or contains a value other than an integer, or contains a float value, the int() function parses the string value to an integer value as per the base if specified. These arguments can not be parsed into an integer value since the string does not have a valid integer value.

Valid arguments in int() function

The following are valid arguments for the built in function int(). If you use one of the below, there will not be any error.

int() function with no argument – The default int() function which has no argument passed returns default value 0.

print int()    # returns 0

int() function with an integer value – If an integer value is passed as an argument in int() function, returns the integer value.

print int(5)   # returns 5

int() functions with a string containing an integer value – If a string having an integer value is passed as an argument in int() function, returns the integer value.

print int('5')   # returns 5

int() function with a float value – If a float value is passed as an argument in int() function, returns the integer part of the value.

print int(5.4)   # returns 5

int() function with a boolean value – If a boolean value is passed as an argument in int() function, returns the integer value for the boolean value.

print int(True)   # returns 1

Invalid arguments in int() function

Below is some of the examples that will cause the error.

int() function with an empty string – The empty string can not be parsed as an integer value

print int('')     # throws ValueError: invalid literal for int() with base 10: ''

int() function with a string having a float value – If a string having a float value is passed as an argument, int() function will throw value error.

print int('5.4')     # throws ValueError: invalid literal for int() with base 10: '5.4'

int() function with a non-integer string – If a string contains a non-integer values such as characters and passed as an argument, the int() function will throw value error.

print int('q')     # throws ValueError: invalid literal for int() with base 10: 'q'

Solution 1

If the string argument contains a float value in the built in function int(), it will throw the error. The string argument should be converted as a float value before it is passed as an argument to the int() function. This will resolve the error.

Program

x='5.4'
print int(x)

Output

Traceback (most recent call last):
  File "/Users/python/Desktop/test.py", line 3, in <module>
    print int(x)
ValueError: invalid literal for int() with base 10: '5.4'
[Finished in 0.1s with exit code 1]

Solution

x='5.4'
print int(float(x))

Output

5
[Finished in 0.0s]

Solution 2

The string represents a number that should be verified using the buid-in function isdigit(). If the function isdigit() returns true, the string contains a valid integer number. It can be passed to the built in function int() as an argument. Otherwise, an error message would be shown to the user.

x='5.4'
if x.isdigit():
	print "Integer value is " , int(x)
else :
	print "Not an integer number"

Output

Not an integer number
[Finished in 0.0s]

Solution 3

If a string occasionally contains a non-integer number, the build-in function isdigit() is not a good choice. In this case, try-except will be used to solve this problem. If an integer is present in the string, it will be executed in the try block. Otherwise, an error message will be displayed to the user in the error block.

x='5.4'
try:
	print ("Integer value is " , int(x))
except:
	print "Not an integer number"

Output

Not an integer number
[Finished in 0.0s]

Solution 4

If a string argument contains an empty string, the built-in function int() will throw an error. The empty string should be validated before it is passed to the int() function.

x=''
if len(x) == 0:
	print "empty string"
else :
	print int(x)

Output

empty string
[Finished in 0.0s]

Solution 5

If the string argument contains a float value in the built in function int(), it will throw the error. The string argument should be verified using an built in function eval() before it is passed as an argument to the int() function. This will resolve the error.

x='2.3'
y = eval(x)
print type(y)
print eval(x)

Output

<type 'float'>
2.3
[Finished in 0.1s]

You are here: Home / Exceptions / ValueError: Invalid Literal For int() With Base 10

Python ValueError: invalid literal for int() with base 10 is an exception which can occur when we attempt to convert a string literal to integer using int() method and the string literal contains characters other than digits. In this article, we will try to understand the reasons behind this exception and will look at different methods to avoid it in our programs.

What is “ValueError: invalid literal for int() with base 10” in Python?

A ValueError is an exception in python which occurs when an argument with the correct type but improper value is passed to a method or function.The first part of the message i.e. “ValueError” tells us that an exception has occurred because an improper value is passed as argument to the int() function. The second part of the message “invalid literal for int() with base 10”  tells us that we have tried to convert an input to integer but the input has characters other than digits in the decimal number system.

Working of int() function

The int() function in python takes a string or a number as first argument and an optional argument base which denotes the number format. The base has a default value 10 which is used for decimal numbers but we can pass a different value  for base such as 2 for binary number or 16 for hexadecimal number. In this article, we will use the int() function with only the first argument and the default value for base will always be zero.  This can be seen in the following examples.

We can convert a floating point number to integer as given in the following example.When we convert a floating point number into integer using int() function, the digits after the decimal are dropped from the number in the output. 


print("Input Floating point number is")
myInput= 11.1
print(myInput)
print("Output Integer is:")
myInt=int(myInput)
print(myInt)

Output:

Input Floating point number is
11.1
Output Integer is:
11

We can convert a string consisting of digits to an integer as given in the following example. Here the input consists of only the digits and hence it will be directly converted into an integer. 

print("Input String is:")
myInput= "123"
print(myInput)
print("Output Integer is:")
myInt=int(myInput)
print(myInt)

Output:

Input String is:
123
Output Integer is:
123

The two input types shown in the above two examples are the only input types for which int() function works properly. With other types of inputs, ValueError will be generated with the message ”invalid literal for int() with base 10” when they are passed as arguments to the int() function. Now , we will look at various types of inputs for which ValueError can be generated in the int() function.

As discussed above, “ValueError: invalid literal for int()” with base 10 can occur when input with an inappropriate value is passed to the int() function. This can happen in the following conditions.

1.Python ValueError: invalid literal for int() with base 10 occurs when input to int() method is alphanumeric instead of numeric and hence the input cannot be converted into an integer.This can be understood with the following example.

In this example, we pass a string containing alphanumeric characters to the int() function due to which ValueError occurs showing a message “ ValueError: invalid literal for int() with base 10”  in the output.

print("Input String is:")
myInput= "123a"
print(myInput)
print("Output Integer is:")
myInt=int(myInput)
print(myInt)

Output:


Input String is:
123a
Output Integer is:
Traceback (most recent call last):

  File "<ipython-input-9-36c8868f7082>", line 5, in <module>
    myInt=int(myInput)

ValueError: invalid literal for int() with base 10: '123a'

2. Python ValueError: invalid literal for int() with base 10 occurs when the input to int() function contains space characters and hence the input cannot be converted into an integer. This can be understood with the following example.

In this example, we pass a string containing space to the int() function due to which ValueError occurs showing a message “ ValueError: invalid literal for int() with base 10”  in the output.

print("Input String is:")
myInput= "12 3"
print(myInput)
print("Output Integer is:")
myInt=int(myInput)
print(myInt)

Output:

Input String is:
12 3
Output Integer is:
Traceback (most recent call last):

  File "<ipython-input-10-d60c59d37000>", line 5, in <module>
    myInt=int(myInput)

ValueError: invalid literal for int() with base 10: '12 3'

3. Python ValueError: invalid literal for int() with base 10 occurs when the input to int() function contains any punctuation marks like period “.” or comma “,”.  Hence the input cannot be converted into an integer.This can be understood with the following example.

In this example, we pass a string containing period character “.” to the int() function due to which ValueError occurs showing a message “ ValueError: invalid literal for int() with base 10”  in the output.

print("Input String is:")
myInput= "12.3"
print(myInput)
print("Output Integer is:")
myInt=int(myInput)
print(myInt)

Output:

Input String is:
12.3
Output Integer is:
Traceback (most recent call last):

  File "<ipython-input-11-9146055d9086>", line 5, in <module>
    myInt=int(myInput)

ValueError: invalid literal for int() with base 10: '12.3'

How to avoid “ValueError: invalid literal for int() with base 10”?

We can avoid the ValueError: invalid literal for int() with base 10 exception using preemptive measures to check if the input being passed to the int() function consists of only digits or not. We can use several ways to check if the input being passed to int() consists of only digits or not as follows.

1.We can use regular expressions to check if the input being passed to the int() function consists of only digits or not. If the input contains characters other than digits, we can prompt the user that the input cannot be converted to integer. Otherwise, we can proceed normally.

In the python code given below, we have defined a regular expression “[^d]” which matches every character except digits in the decimal system. The re.search() method searches for the pattern and if the pattern is found, it returns a match object. Otherwise re.search() method returns None. 

Whenever, re.search() returns None, it can be accomplished that the input has no characters other than digits and hence the input can be converted into an integer as follows.

import re
print("Input String is:")
myInput= "123"
print(myInput)
matched=re.search("[^d]",myInput)
if matched==None:
    myInt=int(myInput)
    print("Output Integer is:")
    print(myInt)
else:
    print("Input Cannot be converted into Integer.")

Output:

Input String is:
123
Output Integer is:
123

If the input contains any character other than digits,re.search() would contain a match object and hence the output will show a message that the input cannot be converted into an integer.

import re
print("Input String is:")
myInput= "123a"
print(myInput)
matched=re.search("[^d]",myInput)
if matched==None:
    myInt=int(myInput)
    print("Output Integer is:")
    print(myInt)
else:
    print("Input Cannot be converted into Integer.")

Output:

Input String is:
123a
Input Cannot be converted into Integer.

2.We can also use isdigit() method to check whether the input consists of only digits or not. The isdigit() method takes a string as input and returns True if the input string passed to it as an argument consists only of digital in the decimal system  . Otherwise, it returns False. After checking if the input string consists of only digits or not, we can convert the input into integers.

In this example, we have used isdigit() method to check whether the given input string consists of only the digits or not. As the input string ”123” consists only of digits, the isdigit() function will return True and the input will be converted into an integer using the int() function as shown in the output.

print("Input String is:")
myInput= "123"
print(myInput)
if myInput.isdigit():
    print("Output Integer is:")
    myInt=int(myInput)
    print(myInt)
else:
    print("Input cannot be converted into integer.")

Output:

Input String is:
123
Output Integer is:
123

If the input string contains any other character apart from digits, the isdigit() function will return False. Hence the input string will not be converted into an integer.

In this example, the given input is “123a” which contains an alphabet due to which isdigit() function will return False and the message will be displayed in the output that the input cannot be converted into integer as shown below.

print("Input String is:")
myInput= "123a"
print(myInput)
if myInput.isdigit():
    print("Output Integer is:")
    myInt=int(myInput)
    print(myInt)
else:
    print("Input cannot be converted into integer.")    

Output:

Input String is:
123a
Input cannot be converted into integer.

3.It may be possible that the input string contains a floating point number and has a period character “.” between the digits. To convert such inputs to integers using the int() function, first we will check if the input string contains a floating point number i.e. it has only one period character between the digits or not using regular expressions. If yes, we will first convert the input into a floating point number which can be passed to int() function and then we will show the output. Otherwise, it will be notified that the input cannot be converted to an integer.

In this example,  “^d+.d$” denotes a pattern which starts with one or more digits, has a period symbol ”.” in the middle and ends with one or more digits which is the pattern for floating point numbers. Hence, if the input string is a floating point number, the re.search() method will not return None and the input will be converted into a floating point number using float() function and then it will be converted to an integer as follows. 

import re
print("Input String is:")
myInput= "1234.5"
print(myInput)
matched=re.search("^d+.d+$",myInput)
if matched!=None:
    myFloat=float(myInput)
    myInt=int(myFloat)
    print("Output Integer is:")
    print(myInt)
else:
    print("Input is not a floating point literal.")

Output:

Input String is:
1234.5
Output Integer is:
1234

If the input is not a floating point literal, the re.search() method will return a None object and  the message will be shown in the output that input is not a floating point literal as follows.

import re
print("Input String is:")
myInput= "1234a"
print(myInput)
matched=re.search("^d+.d$",myInput)
if matched!=None:
    myFloat=float(myInput)
    myInt=int(myFloat)
    print("Output Integer is:")
    print(myInt)
else:
    print("Input is not a floating point literal.")

Output:

Input String is:
1234a
Input is not a floating point literal.

For the two approaches using regular expressions, we can write a single program using groupdict() method after writing named patterns using re.match() object. groupdict() will return a python dictionary of named captured groups in the input and thus can be used to identify the string which can be converted to integer.

4.We can also use exception handling in python using python try except to handle the ValueError whenever the error occurs. In the try block of the code, we will normally execute the code. Whenever ValueError occurs, it will be raised in the try block and will be handled by the except block and a proper message will be shown to the user.

 If the input consists of only the digits and is in correct format, output will be as follows.

print("Input String is:")
myInput= "123"
print(myInput)
try:
    print("Output Integer is:")
    myInt=int(myInput)
    print(myInt)
except ValueError:
    print("Input cannot be converted into integer.")

Output:

Input String is:
123
Output Integer is:
123

If the input contains characters other than digits such as alphabets or punctuation, ValueError will be thrown from the int() function which will be caught by the except block and a message will be shown to the user that the input cannot be converted into integer.

print("Input String is:")
myInput= "123a"
print(myInput)
try:
    print("Output Integer is:")
    myInt=int(myInput)
    print(myInt)
except ValueError:
    print("Input cannot be converted into integer.")

Output:

Input String is:
123a
Output Integer is:
Input cannot be converted into integer.

Conclusion

In this article, we have seen why “ValueError: invalid literal for int() with base 10” occurs in python and have understood the reasons and mechanism behind it. We have also seen that this error can be avoided by first checking if the input to int() function consists of only digits or not using different methods like regular expressions and inbuilt functions. 

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Python-это особый язык, который позволяет очень хорошо обрабатывать ошибки и исключения. Имея тысячи известных исключений и возможность обрабатывать каждое из них, все ошибки легко устраняются из кода. Имея это в виду, мы обсудим ошибку Invalid literal for int() with base 10  (недопустимый литерал для int()) в python.

Ошибка Invalid literal for int() with base 10 возникает при попытке преобразовать недопустимый объект в целое число. В Python функция int() принимает объект, а затем преобразует его в целое число при условии, что он находится в удобочитаемом формате. Поэтому, когда вы пытаетесь преобразовать строку без целых чисел, функция выдаёт ошибку. Эта ошибка относится к категории ValueError, так как значение параметра недопустимо.

ValueError в Python происходит, когда мы передаем неподходящий тип аргумента. Iнедопустимый литерал для int() с базой 10 ошибка вызвана передачей неверного аргумента функции int (). ValueError возникает, когда мы передаем любое строковое представление, отличное от int.

ValueError в Python возникает, когда мы передаем неподходящий тип аргумента. Ошибка недопустимого литерала вызвана передачей неверного аргумента функции int(). Если мы передаем любое строковое представление, отличное от представления int, то генерируется ValueError.

Давайте разберемся в этом подробнее!

ValueError: invalid literal for int() with base 10

Это сообщение об ошибке говорит, что существует недопустимый литерал для целого числа по основанию 10. Эта ошибка означает, что переданное значение не может быть преобразовано.

Рассмотрим пример:

Недопустимый литерал для int() с примером базы 10

Выход

Может случиться так, что мы можем подумать,что при выполнении приведенного выше кода десятичная часть, то есть “.9”, будет усечена, давая выход 1. Однако этого не происходит, поскольку функция int( ) использует десятичную систему счисления в качестве основы для преобразования. Это означает, что база по умолчанию для преобразования равна 10. В десятичной системе счисления мы имеем числа от 0 до 9. Таким образом, int() with может преобразовывать только строковое представление int, а не поплавки или символы.

Может показаться, что при выполнении вышеуказанного кода десятичная часть, т.е. «.9», будет усечена, давая на выходе 1. Однако этого не происходит, поскольку функция int() использует десятичную систему счисления в качестве основы для преобразования. Это означает, что основание для преобразования по умолчанию равна 10. В десятичной системе счисления мы имеем числа от 0 до 9. Таким образом, int() с основанием = 10 может преобразовывать только строковое представление целых чисел (int), а не дробных (float) или символы (char).

Давайте рассмотрим несколько примеров, где эта ошибка может возникнуть:

Пример 1:

пример 1

В этом примере значение “python pool” – это строковое значение, передаваемое функции int(), которое приводит к ошибке.

Пример 2:

пример 2

Поскольку значение, которое мы использовали здесь, является float внутри строки, это приводит к ошибке недопустимого литерала для int().

Пример 3:

пример 3 Недопустимый литерал для int() с основанием 10

В этом примере мы получаем ошибку, так как использовали список внутри строки.

Пример 4:

недопустимый литерал пример 4

Ошибка invalid literal для int() возникает из-за того, что мы использовали кортеж внутри строки.

Пример 5:

словарь внутри строки, который приводит к ошибке

Здесь мы использовали словарь внутри строки, который приводит к ошибке.

Пример 6:

недопустимый литерал для int() с базой 10 пример 6

Ошибка возникает в этом коде, так как мы использовали пустую строку в функции int().

Разрешение ошибки: invalid literal for int() with base 10:

Использование float() для преобразования десятичных чисел:

Здесь мы сначала преобразовали строковое представление в float с помощью функции float(). Затем мы использовали функцию int() для преобразования его в целое число.

Использование try-catch для разрешения invalid literal for int() with base 10

try:
   ("12.1")
except:
    print("Error in converting to string")

Здесь мы использовали конструкцию try-catch, чтобы избавиться от ошибки invalid literal for int() with base 10. Если ошибка возникает внутри блока try, она перехватывается в блоке catch, тем самым предотвращая ошибку.

Использование isdigit():

x="12"
if x.isdigit():
    x=int(x)
    print(type(x))
<class 'int'>

В этом примере мы сначала убеждаемся, что содержимое внутри строки является целочисленным, используя метод isdigit(). В результате ошибка не возникает.

Использование isnumeric():

x="12"
if x.isnumeric():
    x=int(x)
    print(type(x))
<class 'int'>

isnumeric() это метод строки который возвращает логическое значение, указывающее, является ли строка числом. Если строка содержит число, то мы преобразуем его в int, иначе нет.

Вывод:

На этом мы заканчиваем нашу статью. Это был простой способ избавиться от ValueError в Python. Если вышеприведенный метод не работает, то необходимо проверить строку и убедиться, что она не содержит ни одной буквы.

Однако, если у вас есть какие-либо сомнения или вопросы, дайте мне знать в разделе комментариев ниже. Я постараюсь помочь вам как можно скорее.

Счастливого кодирования!

Invalid literal for int() with base 10 occurs when you try to convert an invalid object into an integer. Python is good at converting between different data types. When using the int() function, we must follow a specific set of rules. If we do not follow these rules, we will raise a ValueError There are two causes of this particular ValueError:

  1. If we pass a string containing anything that is not a number, this includes letters and special characters.
  2. If we pass a string-type object to int() that looks like a float type.

To solve or avoid the error, ensure that you do not pass int() any letters or special characters.

This tutorial will go through the error in detail and how to solve it with examples.


Table of contents

  • What is a ValueError?
  • Passing Non-numerical Arguments to int()
  • Passing Float-like Strings to int()
  • Rounding Floats
  • Summary

What is a ValueError?

In Python, a value is the information stored within a certain object. You will encounter a ValueError in Python when you use a built-in operation or function that receives an argument that has the right type but an inappropriate value. Let’s look at an example of converting several a ValueError:

value = 'string'

print(float(value))
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
print(float(value))

ValueError: could not convert string to float: 'string'

The above code throws the ValueError because the value ‘string‘ is an inappropriate (non-convertible) string. You can only convert numerical strings using the float() method, for example:

value = '5'
print(float(value))
5.0

The code does not throw an error because the float function can convert a numerical string. The value of 5 is appropriate for the float function.

For further reading of ValueError, go to the article: How to Solve Python ValueError: cannot convert float nan to integer.

Passing Non-numerical Arguments to int()

If we pass an argument to int() that contains letters or special characters, we will raise the invalid literal ValueError.

An integer is a whole number, so the argument provided should only have real numbers.

Let’s take the example of a program that takes an input and performs a calculation on the input.

value_1 = input("Enter the first value:  ")

value_2 = input("Enter the second value:   ")

sum_values = value_1 + value_2

print("nThe sum is:  ", sum_values)
Enter the first value:  4

Enter the second value:   6

The sum is:   46

In this example, the program interprets the two inputs as string-type and concatenates them to give “46”. However, we want the program to interpret the two inputs as integer-type to calculate the sum. We need to convert the values to integers before performing the sum as follows:

value_1 = input("Enter the first value:  ")

value_2 = input("Enter the second value:   ")

sum_values = int(value_1) + int(value_2)

print("nThe sum is:  ", sum_values)
Enter the first value:  4

Enter the second value:   6

The sum is:   10

The code successfully runs, but the ValueError may still occur if the user inputs a value that is not an integer. Let’s look at an example, with the input “science”:

value_1 = input("Enter the first value:  ")

value_2 = input("Enter the second value:   ")

sum_values = int(value_1) + int(value_2)

print("nThe sum is:  ", sum_values)
Enter the first value:  4

Enter the second value:   science

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
sum = int(x) + int(y)

ValueError: invalid literal for int() with base 10: 'science'

The ValueError tells us that “science” is not a number. We can solve this by putting the code in a try/except block to handle the error.

value_1 = input("Enter the first value:  ")

value_2 = input("Enter the second value:   ")

try:

    sum_values = int(x) + int(y)

    print("nThe sum is:  ", sum_values)

except ValueError:

    print("nYou have entered one or more values that are not whole numbers.")

You have entered one or more values that are not whole numbers

The code has an exception handler that will tell the user that the input values are not whole numbers.

Passing Float-like Strings to int()

If you pass a string-type object that looks like a float type, such as 5.3, you will also raise the ValueError. In this case, Python detects the “.” as a special character. We cannot pass strings or special characters to the int() function.

int('5.3')
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
1 int('5.3')

ValueError: invalid literal for int() with base 10: '5.3'

Let’s look at a bakery with a program to calculate whether it has enough cakes in stock to serve customers for the day. The input field must accept decimal numbers because cakes can be half consumed, quarter consumed, etc. We are only interested in integer level precision, not half cakes or quarter cakes, so we convert the input to an integer. We can use an if statement to check whether the bakery has more than a specified number of cakes. If there are not enough cakes, the program will inform us through a print statement. Otherwise, it will print that the bakery has enough cakes for the day. The program can look as follows:

cakes = input("How many cakes are left:  ")

cakes_int = int(cakes)

if cakes_int > 8:

    print('We have enough cakes!")

else:

    print("We do not have enough cakes!")

Let’s run the code with an input of “5.4” as a string.

Enter how many cakes are left:  5.4   

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
1 cakes = int(cakes)

ValueError: invalid literal for int() with base 10: '5.4'

The ValueError occurs because we try to convert “5.4”, a string, as an integer. Python cannot convert a floating-point number in a string to an integer. To solve this issue, we need to convert the input to a floating-point number to convert to an integer. We can use the float() function, which returns a floating-point representation of a float, and the int() function produces an integer.

cakes = input("How many cakes are left:  ")

cakes_int = int(float(cakes))

if cakes_int > 8:

    print('We have enough cakes!")

else:

    print("We do not have enough cakes!")

Enter how many cakes are left:  5.4   

We do not have enough cakes!

The code successfully runs, with the conversion of the input to a float, the program can convert it to an integer. Based on the output, the bakery has more baking to do!

Rounding Floats

Using the int() function works with floats. However, the function will truncate everything after the decimal without rounding to the nearest integer.

cakes = float("5.7")

print(int(cakes))
5

We can see 5.7 is closer to 6 than 5, but the int() function truncates regardless of the decimal value. If it is more suitable to round floats to the nearest integer, you can use the round() function. We can make the change to the code as follows:

cakes = float("5.7")

rounded_cakes = round(cakes, 0)

print(int(cakes))
6

The second argument of the round() function specifies how many decimal places we want. We want to round to zero decimal places or the nearest integer in this example.

Summary

Congratulations on completing this tutorial! You know how the ValueError: invalid literal int() base 10 occurs and how to solve it like an expert. To summarize, integers are whole numbers, so string-type objects passed to the int() function should only contain positive or negative numbers. If we want to give a string-type object that looks like a float, int() will raise the ValueError due to the presence of the “.” special character. You must convert float-like strings to a floating-point object first and then convert to an integer. You can use the round() function to ensure the int() function does not incorrectly truncate a number and specify the number of decimal places.

Generally, ValueError occurs when the value or values used in the code do not match what the Python interpreter expects. Another common ValueError is ValueError: too many values to unpack (expected 2)

You can find other solutions to Python TypeErrors, such as TypeError: can only concatenate str (not “int”) to str, SyntaxError: unexpected EOF while parsing, and TypeError: list indices must be integers or slices, not str. If you want to learn how to write Python programs specific to data science and machine learning, I provide a compilation of the best online courses on Python for data science and machine learning.

Have fun and happy researching!

Python ValueError: invalid literal for int() with base 10

ValueError: invalid literal for int() with base 10:

While using the int() function, there are some strict rules which we must follow.

This error is triggered in one of two cases:

  1. When passing a string containing anything that isn’t a number to int(). Unfortunately, integer-type objects can’t have any letters or special characters.
  2. When passing int() a string-type object which looks like a float-type (e.g., the string '56.3'). Although technically, this is an extension of the first error case, Python recognizes the special character .inside the string '56.3'.

To avoid the error, we shouldn’t pass int() any letters or special characters.

We’ll look at a specific example for each of these causes, along with how to implement a solution.

As mentioned previously, one of the most common causes of the ValueError we’ve been looking at is passing int() an argument that contains letters or special characters.

By definition, an integer is a whole number, so an integer-type object should only have numbers (+ and - are also acceptable). As a result, Python will throw an error when attempting to convert letters into an integer.

This error can frequently occur when converting user-input to an integer-type using the int() function. This problem happens because Python stores the input as a string whenever we use input().

As a result, if you’d like to do some calculations using user input, the input needs to be converted into an integer or float.

Let’s consider a basic example and create a short program that will find the sum of two values input by the user:

val_1 = input("Enter the first value: ")
val_2 = input("Enter the second value: ")

new_val = val_1 + val_2

print("nThe sum is: ", new_val)

Out:

Enter the first value:  5
Enter the second value:  3

As you can see, we received «53» instead of the correct sum, «8». We received this output because the input must be converted to integer-type to calculate the sum correctly. We have instead added two strings together through concatenation.

So, we need to convert the values to integers before summing them, like so:

val_1 = input("Enter the first value: ")
val_2 = input("Enter the second value: ")

new_val = int(val_1) + int(val_2)

print("nThe sum is: ", new_val)

Out:

Enter the first value:  5
Enter the second value:  3

We’re now getting the correct answer.

Despite working as expected, problems can occur if users start inputting values that aren’t integers.

In the example below, we have entered «Hello» as the second input:

val_1 = input("Enter the first value: ")
val_2 = input("Enter the second value: ")

new_val = int(val_1) + int(val_2)

print("nThe sum is: ", new_val)

Out:

Enter the first value:  5
Enter the second value:  Hello

Out:

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-3-697a6feaa0ed> in <module>
      2 val_2 = input("Enter the second value: ")
      3 
----> 4 new_val = int(val_1) + int(val_2)
      5 
      6 print("nThe sum is: ", new_val)
ValueError: invalid literal for int() with base 10: 'Hello'

We now have an error because the value val_2 is 'Hello', which isn’t a number. We can fix this by using a simple try/except block, like in the following solution.

In this scenario, there isn’t much that can be done about users testing the limits of our program. One potential solution is adding an exception handler to catch the error and alert the user that their entry was invalid.

val_1 = input("Enter the first value: ")
val_2 = input("Enter the second value: ")

try:
    new_val = int(val_1) + int(val_2)
    print("nThe sum is: ", new_val)
except ValueError:
    print("nWhoops! One of those wasn't a whole number")

Out:

Enter the first value:  5
Enter the second value:  Hello

Out:

Whoops! One of those wasn't a whole number

Using an exception handler here, the user will receive a warning message whenever int() throws a ValueError. This solution is a common way to handle user input that will be cast to integers.

Passing int() a string-type object which looks like a float (e.g. '56.9'), will also trigger the ValueError.

In this scenario, Python detects the ., which is a special character, causing the error. For example, here’s what happens when we pass '56.3' to int() as an argument:

Out:

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-7-4ff8ba29c4d7> in <module>
----> 1 int("56.9")

ValueError: invalid literal for int() with base 10: '56.9'

int() works with floats, so the simplest way to fix the error, in this case, is to convert our string to a floating-point number first. After converting the string-type to float-type, we can successfully pass our object to the int() function:

val = float("56.9")
int(val)

The main problem with this approach is that using int() on a float will cut off everything after the decimal without round to the nearest integer.

56.9 is much closer to 57 than 56, but int() has performed a simple truncation to eliminate the decimal.

For situations where you’d prefer to round floats to their closest integer, you can add an intermediate step using the round() function, like so:

val = float("56.9")
rounded_val = round(val, 0)
int(rounded_val)

Specifying zero as our second round() argument communicates to Python that we’d like to round val to zero decimal places (forming an integer). By altering the second argument, we can adjust how many decimal numbers Python should use when rounding.

As we’ve discussed, passing an argument that contains letters or special characters to the int() function causes this error to occur. Integers are whole numbers, so any string-type objects passed to int()should only contain numbers, +or -.

In cases where we’d like to convert a string-type object that looks like float (e.g. '56.3') into an integer, we will also trigger the error. The error happens due to the presence of the .character. We can easily avoid the error by converting the string to a floating-point object first, as follows:

In cases where we’d like a number to remain a decimal, we could drop the int() function altogether and use float() to make the object a float-type. Ultimately, if you’re experiencing this error, it’s a good idea to think about what’s going into the int() function and why that could be causing problems.

The error is straightforward to resolve once you get to the bottom of what’s causing the issue.

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    ValueError is encountered when we pass an inappropriate argument type. Here, we are talking about the ValueError caused by passing an incorrect argument to the int() function. When we pass a string representation of a float or any string representation other than that of int, it gives a ValueError.

    Example 1 : ValueError with base 10.

    Output :

    ValueError: invalid literal for int() with base 10: '23.5'

    One can think that while executing the above code, the decimal part ‘.5’ should be truncated and the code should give output as 23 only. But the point to be noted is that the int( ) function uses the decimal number system as its base for conversion ie. base = 10 is the default value for conversion. And in the decimal number system, we have numbers from 0 to 9 excluding the decimal (.) and other characters(alphabets and special chars). Therefore, int() with base = 10 can only convert a string representation of int and not floats or chars.

    We can first convert the string representation of float into float using float() function and then convert it into an integer using int().

    print(int(float('23.5')))

    Output :

    23

    Example 2 : Passing alphabets in int().

    Output :

    invalid literal for int() with base 10: 'abc'

    The chars a, b, c, d, e, and f are present in the base =16 system and therefore only these chars along with digits 0 to 9 can be converted from their string representation to integer in hexadecimal form. We have to pass an parameter base with value 16.

    print(int('abc', base = 16))

    Output :

    2748

    ValueError occurs when we pass an invalid argument type. The error is raised when we call int() function with string argument which Python cannot parse and throws ValueError: invalid literal for int() with base 10: ”

    Let’s look at some examples and the solution to fix the ValueError in Python.

    Example – Converting float to integer

    If you look at the below example, we are trying to convert the input value into an integer that means we expect that the input field weight is always an integer value. 

    However, the user can enter weight even in decimal value, and when we try to convert it into an integer, Python throws invalid literal for int() with base 10 error.

    number= input("What is your weight:")
    kilos=int(number)
    print ("The weight of the person is:" + str(kilos))
    
    # Output
    What is your weight:55.5
    Traceback (most recent call last):
      File "c:ProjectsTryoutslistindexerror.py", line 2, in <module>
        kilos=int(number)
    ValueError: invalid literal for int() with base 10: '55.5'

    One can think that while executing the above code, Python will automatically truncate the decimal value and retain only the integer part. The int() function uses the decimal number system as base conversion, meaning base=10 is the default value for transformation. Therefore it can only convert the string representation of int, not the decimal or float or chars.

    Solution 1: We can first convert the input number into a float using float() method, parse the decimal digits, and convert them again into an integer, as shown below.

    number= input("What is your weight:")
    kilos=int(float(number))
    print ("The weight of the person is:" + str(kilos))
    
    # Output
    What is your weight:55.5
    The weight of the person is:55

    Solution 2: There can be other possible issues where the entered input value itself might be in the string, so converting the string value will throw a Value Error even if we use the above method.

    So better way to solve this is to ensure the entered input is a numeric digit or not. Python has isdigit() method, which returns true in case of a numeric value and false if it’s non-numeric.

    number= input("What is your weight:")
    if number.isdigit():
        kilos=int(float(number))
        print ("The weight of the person is:" + str(kilos))
    else:
        print("Error - Please enter a proper weight")
    
    # Output
    What is your weight:test
    Error - Please enter a proper weight

    Solution 3: The other common way to handle this kind of errors is using try except

    number= input("What is your weight:")
    try:
        kilos=int(float(number))
        print ("The weight of the person is:" + str(kilos))
    except:
        print("Error - Please enter a proper weight")
    
    # Output
    What is your weight:test
    Error - Please enter a proper weight

    Conclusion

    ValueError: invalid literal for int() with base 10 occurs when you convert the string or decimal or characters values not formatted as an integer.

    To solve the error, you can use the float() method to convert entered decimal input and then use the int() method to convert your number to an integer. Alternatively, you can use the isdigit() method to check if the entered number is a digit or not, and the final way is to use try/except to handle the unknown errors.

    Avatar Of Srinivas Ramakrishna

    Srinivas Ramakrishna is a Solution Architect and has 14+ Years of Experience in the Software Industry. He has published many articles on Medium, Hackernoon, dev.to and solved many problems in StackOverflow. He has core expertise in various technologies such as Microsoft .NET Core, Python, Node.JS, JavaScript, Cloud (Azure), RDBMS (MSSQL), React, Powershell, etc.

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