Remove empty strings from a list of Strings in Python

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Borislav Hadzhiev

Last updated: Aug 16, 2022

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Remove empty strings from a list of Strings in Python #

Use a list comprehension to remove the empty strings from a list of strings, e.g. new_list = [item for item in my_list if item]. The list comprehension will return a new list that doesn't contain any empty strings.

main.py
# ✅ Remove empty strings from a list (using list comprehension) my_list = ['one', '', 'two', '', 'three', ''] new_list = [item for item in my_list if item] print(new_list) # 👉️ ['one', 'two', 'three'] # --------------------------------------------- # ✅ Remove empty strings from a list (using filter()) new_list = list(filter(None, my_list)) print(new_list) # 👉️ ['one', 'two', 'three'] # --------------------------------------------- # ✅ Remove empty strings from a list (using for loop) for item in my_list.copy(): if item == '': my_list.remove(item) print(my_list) # 👉️ ['one', 'two', 'three']

The first example uses a list comprehension to remove the empty strings from a list.

List comprehensions are used to perform some operation for every element or select a subset of elements that meet a condition.
main.py
my_list = ['one', '', 'two', '', 'three', ''] new_list = [item for item in my_list if item] print(new_list) # 👉️ ['one', 'two', 'three']

On each iteration, we check if the current item is truthy and return the result.

Empty strings are falsy values, so they get filtered out.

The list comprehension creates a new list, it doesn't mutate the original list.

If you want to remove the empty strings from the original list, use list slicing.

main.py
my_list = ['one', '', 'two', '', 'three', ''] my_list[:] = [item for item in my_list if item] print(my_list) # 👉️ ['one', 'two', 'three']

We used the my_list[:] syntax to get a slice that represents the entire list, so we can assign to the variable directly.

The slice my_list[:] represents the entire list, so when we use it on the left-hand side, we are assigning to the entire list.

This approach changes the contents of the original list.

Alternatively, you can use the filter() function.

Remove empty strings from a list of Strings using filter() #

To remove the empty strings from a list of strings:

  1. Use the filter() function to filter out the empty strings.
  2. Use the list() class to convert the filter object to a list.
  3. The new list won't contain any empty strings.
main.py
my_list = ['one', '', 'two', '', 'three', ''] new_list = list(filter(None, my_list)) print(new_list) # 👉️ ['one', 'two', 'three']

We used the filter() function to remove the empty strings from a list.

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.

An empty string is a falsy value, so all empty strings get removed.

The last step is to use the list() class to convert the filter object to a list.

Alternatively, you can use a for loop.

Remove empty strings from a list of Strings using for loop #

To remove the empty strings from a list of strings:

  1. Use a for loop to iterate over a copy of the list.
  2. On each iteration, check if the current item is an empty string.
  3. Use the list.remove() method to remove the empty strings.
main.py
my_list = ['one', '', 'two', '', 'three', ''] for item in my_list.copy(): if item == '': my_list.remove(item) print(my_list) # 👉️ ['one', 'two', 'three']

We used the list.copy() method to get a copy of the list.

main.py
my_list = ['one', '', 'two', '', 'three', ''] # 👇️ ['one', '', 'two', '', 'three', ''] print(my_list.copy())

The list.copy method returns a shallow copy of the object on which the method was called.

This is necessary because we aren't allowed to remove items from a list while iterating over it.

However, we can iterate over a copy of the list and remove items from the original list.

main.py
my_list = ['one', '', 'two', '', 'three', ''] for item in my_list.copy(): if item == '': my_list.remove(item) print(my_list) # 👉️ ['one', 'two', 'three']
On each iteration, we check if the current item is an empty string and use the list.remove() method to remove the matching elements.

The list.remove() method removes the first item from the list whose value is equal to the passed in argument.

The remove() method mutates the original list and returns None.

The most important thing to note when removing items from a list in a for loop is to use the list.copy() method to iterate over a copy of the list.

If you try to iterate over the original list and remove items from it, you might run into difficult to locate bugs.

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