Remove all empty elements from a list in Python

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Borislav Hadzhiev

Last updated: Aug 16, 2022

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Remove all empty elements from a list in Python #

Use a list comprehension to remove all empty elements from a list, 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 elements.

main.py
# ✅ Remove empty elements from a list (using list comprehension) my_list = ['a', '', [], (), None, 'b', '', 'c'] new_list = [item for item in my_list if item] print(new_list) # 👉️ ['a', 'b', 'c'] # --------------------------------------------- # ✅ Remove empty elements from a list (using filter()) new_list = list(filter(None, my_list)) print(new_list) # 👉️ ['a', 'b', 'c'] # --------------------------------------------- # ✅ Remove empty elements from a list (using for loop) for item in my_list.copy(): if not item: my_list.remove(item) print(my_list) # 👉️ ['a', 'b', 'c']

The first example uses a list comprehension to remove the falsy values 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 = ['a', '', [], (), None, 'b', '', 'c'] new_list = [item for item in my_list if item] print(new_list) # 👉️ ['a', 'b', 'c']

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

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).
In other words, the list comprehension filters out None, False, empty string, empty list, empty tuple, etc from the list.

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

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

main.py
my_list = ['a', '', [], (), None, 'b', '', 'c'] my_list[:] = [item for item in my_list if item] print(my_list) # 👉️ ['a', 'b', 'c']

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 all empty elements from a list using filter() #

To remove the empty elements from a list:

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

We used the filter() function to remove the empty elements 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.

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 all empty elements from a list using a for loop #

To remove the empty elements from a list:

  1. Use a for loop to iterate over a copy of the list.
  2. On each iteration, check if the current item is falsy.
  3. Use the list.remove() method to remove the empty elements.
main.py
my_list = ['a', '', [], (), None, 'b', '', 'c'] for item in my_list.copy(): if not item: my_list.remove(item) print(my_list) # 👉️ ['a', 'b', 'c']
On each iteration, we check if the current item falsy 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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