Empty separator python ошибка

TLDR:
If you don’t specify a character for str.split to split by, it defaults to a space or tab character. My error was due to the fact that I did not have a space between my quotes.

In case you were wondering, the separator I specified is a space:

words = stuff.split(" ")

The string in question is This is an example of a question.
I also tried # as the separator and put #‘s into my sentence and got the same error.

Edit: Here is the complete block

def break_words(stuff):
"""This function will break up words for us."""
    words = stuff.split(" ")
    return words
sentence = "This is an example of a sentence."
print break_words(sentence)

When I run this as py file, it works.
but when I run the interpreter, import the module, and type:
sentence = "This is an example of a sentence."
followed by print break_words(sentence)

I get the above mentioned error.

And yes, I realise that this is redundant, I’m just playing with functions.

Edit 2: Here is the entire traceback:

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "ex25.py", line 6, in break_words
words = stuff.split(' ')

Edit 3: Well, I don’t know what I did differently, but when I tried it again now, it worked:

>>> s = "sdfd dfdf ffff"
>>> ex25.break_words(s)
['sdfd', 'dfdf', 'ffff']
>>> words = ex25.break_words(s)
>>>

As you can see, no errors.

If you pass an empty string to the str.split() method, you will raise the ValueError: empty separator. If you want to split a string into characters you can use list comprehension or typecast the string to a list using list().

def split_str(word):
    return [ch for ch in word]

my_str = 'Python'

result = split_str(my_str)
print(result)

This tutorial will go through the error in detail with code examples.

Python ValueError: empty separator

In Python, a value is information stored within a particular object. We will encounter a ValueError in Python when we use an operation or function that receives an argument with the right type but an inappropriate value.

The split() method splits a string into a list. We can specify the separator, and the default is whitespace if we do not pass a value for the separator. In this example, an empty separator "" is an inappropriate value for the str.split() method.

Example #1: Split String into Characters

Let’s look at an example of trying to split a string into a list of its characters using the split() method.

my_str = 'research'

chars = my_str.split("")

print(chars)

Let’s run the code to see what happens:

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
Input In [7], in <cell line: 3>()
      1 my_str = 'research'
----> 3 chars = my_str.split("")
      5 print(chars)

ValueError: empty separator

The error occurs because did not pass a separator to the split() method.

Solution #1: Use list comprehension

We can split a string into a list of characters using list comprehension. Let’s look at the revised code:

my_str = 'research'

chars = [ch for ch in my_str]

print(chars)

Let’s run the code to get the list of characters:

['r', 'e', 's', 'e', 'a', 'r', 'c', 'h']

Solution #2: Convert string to a list

We can also convert a string to a list of characters using the built-in list() method. Let’s look at the revised code:

my_str = 'research'

chars = list(my_str)

print(chars)

Let’s run the code to get the result:

['r', 'e', 's', 'e', 'a', 'r', 'c', 'h']

Example #2: Split String using a Separator

Let’s look at another example of splitting a string.

my_str = 'research is fun'

list_of_str = my_str.split("")

print(list_of_str)

In the above example, we want to split the string by the white space between each word. Let’s run the code to see what happens:

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
Input In [10], in <cell line: 3>()
      1 my_str = 'research.is.fun'
----> 3 list_of_str = my_str.split("")
      5 print(list_of_str)

ValueError: empty separator

The error occurs because "" is an empty separator and does not represent white space.

Solution

We can solve the error by using the default value of the separator, which is white space. We need to call the split() method without specifying an argument to use the default separator. Let’s look at the revised code:

my_str = 'research is fun'

list_of_str = my_str.split()

print(list_of_str)

Let’s run the code to see the result:

['research', 'is', 'fun']

Summary

Congratulations on reading to the end of this tutorial!

For further reading on Python ValueErrors, go to the articles:

• How to Solve Python ValueError: year is out of range
• How to Solve Python ValueError: dictionary update sequence element #0 has length N; 2 is required

To learn more about Python for data science and machine learning, go to the online courses page on Python for the most comprehensive courses available.

Have fun and happy researching!

Summary: You can split a string using an empty separator using –
(i) list constructor
(ii) map+lambda
(iii) regex
(iv) list comprehension

Minimal Example:

text = '12345'

# Using list()
print(list(text))

# Using map+lambda
print(list(map(lambda c: c, text)))

# Using list comprehension
print([x for x in text])

# Using regex
import re
# Approach 1
print([x for x in re.split('', text) if x != ''])
# Approach 2
print(re.findall('.', text))

Problem Formulation

📜Problem: How to split a string using an empty string as a separator?

Example: Consider the following snippet –

a = 'abcd'
print(a.split(''))

Output:

Traceback (most recent call last):
  File "C:UsersSHUBHAM SAYONPycharmProjectsFinxterBlogsFinxter.py", line 2, in <module>
    a.split('')
ValueError: empty separator

Expected Output:

['a', 'b', 'c', 'd']

So, this essentially means that when you try to split a string by using an empty string as the separator, you will get a ValueError. Thus, your task is to find out how to eliminate this error and split the string in a way such that each character of the string is separately stored as an item in a list.

Now that we have a clear picture of the problem let us dive into the solutions to solve the problem.

Method 1: Use list()

Approach: Use the list() constructor and pass the given string as an argument within it as the input, which will split the string into separate characters.

Note: list() creates a new list object that contains items obtained by iterating over the input iterable. Since a string is an iterable formed by combining a group of characters, hence, iterating over it using the list constructor yields a single character at each iteration which represents individual items in the newly formed list.

Code:

a = 'abcd'
print(list(a))

# ['a', 'b', 'c', 'd']

🌎Related Read: Python list() — A Simple Guide with Video

Method 2: Use map() and lambda

Approach: Use the map() to execute a certain lambda function on the given string. All you need to do is to create a lambda function that simply returns the character passed to it as the input to the map object. That’s it! However, the map method will return a map object, so you must convert it to a list using the list() function.

Code:

a = 'abcd'
print(list(map(lambda c: c, a)))

# ['a', 'b', 'c', 'd']

Method 3: Use a list comprehension

Approach: Use a list comprehension that returns a new list containing each character of the given string as individual items.

Code:

a = 'abcd'
print([x for x in a])
# ['a', 'b', 'c', 'd']

🌎Related Read: List Comprehension in Python — A Helpful Illustrated Guide

Method 4: Using regex

The re.findall(pattern, string) method scans string from left to right, searching for all non-overlapping matches of the pattern. It returns a list of strings in the matching order when scanning the string from left to right.

🌎Related Read: Python re.findall() – Everything You Need to Know

Approach: Use the regular expression re.findall('.',a) that finds all characters in the given string ‘a‘ and stires them in a list as individual items.

Code:

import re
a = 'abcd'
print(re.findall('.',a))

# ['a', 'b', 'c', 'd']

Alternatively, you can also use the split method of the regex library in a list comprehension which returns each character of the string and eliminates empty strings.

Code:

import re
a = 'abcd'
print([x for x in re.split('',a) if x!=''])

# ['a', 'b', 'c', 'd']

🌎Related Read: Python Regex Split

Do you want to master the regex superpower? Check out my new book The Smartest Way to Learn Regular Expressions in Python with the innovative 3-step approach for active learning: (1) study a book chapter, (2) solve a code puzzle, and (3) watch an educational chapter video.

Conclusion

Hurrah! We have successfully solved the given problem using as many as four (five, to be honest) different ways. I hope this article helped you and answered your queries. Please subscribe and stay tuned for more interesting articles and solutions in the future.

Happy coding! 🙂

Regex Humor

words = stuff.split(" ")

def break_words(stuff):
"""This function will break up words for us."""
    words = stuff.split(" ")
    return words
sentence = "This is an example of a sentence."
print break_words(sentence)

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "ex25.py", line 6, in break_words
words = stuff.split(' ')

>>> s = "sdfd dfdf ffff"
>>> ex25.break_words(s)
['sdfd', 'dfdf', 'ffff']
>>> words = ex25.break_words(s)
>>>

7 ответов

Лучший ответ

def breakWords(stuff):
    """this function will break up words."""
    words = stuff.split(" ")
    return words

>>> s="abc def ghi jkl"
>>> s.split(" ")
['abc', 'def', 'ghi', 'jkl']
>>> s.split("")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: empty separator
>>> 

sentence = "bla mla gla dla"
sentence.split()

4 ответа

>>> list('1111')
['1', '1', '1', '1']

>>> map(None, '1111')
['1', '1', '1', '1']

$ python -m timeit "list('1111')"
1000000 loops, best of 3: 0.483 usec per loop
$ python -m timeit "map(None, '1111')"
1000000 loops, best of 3: 0.431 usec per loop

>>> list('1111')
['1', '1', '1', '1']

>>> [i for i in '1111']
['1', '1', '1', '1']

>>> some_string = '12345'
>>> [some_string[i:i+2] for i in range(0, len(some_string), 2)]
['12', '34', '5']

>>> for char in '11111':
...   print char
... 
1
1
1
1
1
>>> '11111'[4]
'1'

>>> for char in list('11111'):
...   print char
... 
1
1
1
1
1
>>> list('11111')[4]
'1'

>>> list('11111').append('2')
>>> l = list('11111')
>>> l.append(2)
>>> l
['1', '1', '1', '1', '1', 2]

>>> l.append('2')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'str' object has no attribute 'append'

>>> l += '2'
>>> l
'111112'

s="Amalraj"
l=[i for i in s]
print(l)

['A', 'm', 'a', 'l', 'r', 'a', 'j']

s="Amalraj"
l=list(s)
print(l)

['A', 'm', 'a', 'l', 'r', 'a', 'j']

import re; # importing regular expression module
s="Amalraj"
l=re.findall('.',s)
print(l)

['A', 'm', 'a', 'l', 'r', 'a', 'j']