Split a string by comma in Python

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Borislav Hadzhiev

Last updated: Jun 24, 2022

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Split a string by comma in Python #

Use the str.split() method to split a string by comma, e.g. my_list = my_str.split(','). The str.split method will split the string on each occurrence of a comma and will return a list containing the results.

main.py
# ✅ split string on each occurrence of comma my_str = 'one,two,three,four' my_list = my_str.split(',') print(my_list) # 👉️ ['one', 'two', 'three', 'four'] # ✅ split string on each space or comma my_str_2 = 'one two,three four five' my_list_2 = my_str_2.replace(',', ' ').split(' ') print(my_list_2) # 👉️ ['one', 'two', 'three', 'four', 'five']

The str.split() method splits the original string into a list of substrings using a delimiter.

The method takes the following 2 parameters:

NameDescription
separatorSplit the string into substrings on each occurrence of the separator
maxsplitAt most maxsplit splits are done (optional)

If the separator is not found in the string, a list containing only 1 element is returned.

main.py
my_str = 'one' my_list = my_str.split(',') # 👇️ ['one'] print(my_list)

If you have whitespace between the comma-separated words in the string and need to remove it, use the str.strip() method.

main.py
my_str = 'one , two , three ,four' my_list = [item.strip() for item in my_str.split(',')] print(my_list) # 👉️ ['one', 'two', 'three', 'four']

We used a list comprehension to remove the leading and trailing whitespace from each string.

List comprehensions are used to perform some operation for every element, or select a subset of elements that meet a condition.

The str.strip method returns a copy of the string with the leading and trailing whitespace removed.

If your string starts with or ends with a comma, you would get empty string elements in the list.

main.py
my_str = ',one,two,three,four,' my_list = my_str.split(',') print(my_list) # 👉️ ['', 'one', 'two', 'three', 'four', '']

You can use the filter() function to remove any empty strings from the list.

main.py
my_str = ',one,two,three,four,' my_list = list(filter(None, my_str.split(','))) print(my_list) # 👉️ ['one', 'two', 'three', 'four']

The filter function takes a function and an iterable as arguments and constructs an iterator from the elements of the iterable for which the function returns a truthy value.

If you pass None for the function argument, all falsy elements of the iterable are removed.

All values that are not truthy are considered falsy. The falsy values in Python are:

  • constants defined to be falsy: None and False.
  • 0 (zero) of any numeric type
  • empty sequences and collections: "" (empty string), () (empty tuple), [] (empty list), {} (empty dictionary), set() (empty set), range(0) (empty range).

Note that the filter() function returns a filter object, so we have to use the list() class to convert the filter object to a list.

If you need to split a string on occurrences of a comma and another character, replace the comma with the other character and split on that character.
main.py
my_str = 'one,two,three,four' my_str_2 = 'one two,three four five' my_list_2 = my_str_2.replace(',', ' ').split(' ') print(my_list_2) # 👉️ ['one', 'two', 'three', 'four', 'five']

We replaced all occurrences of a comma with a space and split the string on each space.

You could achieve the same result by replacing each occurrence of a space with a comma and splitting on each comma.

main.py
my_str = 'one,two,three,four' my_str_2 = 'one two,three four five' my_list_2 = my_str_2.replace(' ', ',').split(',') print(my_list_2) # 👉️ ['one', 'two', 'three', 'four', 'five']
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