Replacing items in a list using Python

This tutorial will show you how to replace certain values, strings or numbers in a given list. You can use the built-in function replace() for string or the map function for other data types in python.

This tutorial will show you how to replace certain values, strings or numbers in a given list.

# List of items
list_items = ['apple', 'banana', 'cherry', 1, 2, 3]

# Element to replace
element_to_replace = 'cherry'

# New element
new_element = 'mango'

# Replacing in a list
list_items = [i if i != element_to_replace else new_element for i in list_items]
print(list_items)  # ['apple', 'banana', 'mango', 1, 2, 3]

The map function can be used when you want to replace multiple elements:

# List of items
list_items = ['apple', 'banana', 'cherry', 1, 2, 3]

# Elements to replace (can be any data type)
elements_to_replace = ['apple', 1]

# New elements
new_elements = ['mango', 4]

# Replacing in a list
list_items = list(map(lambda x: new_elements[elements_to_replace.index(x)] if x in elements_to_replace else x, list_items))
print(list_items)  # ['mango', 'banana', 'cherry', 4, 2, 3]

In both examples above, we replace the elements 'apple' and 1 in our original list with 'mango' and 4 respectively. The function index() is used to get the index of a value in another list. If the value isn’t found in the new list (i.e., if it doesn’t have an index), index() throws a ValueError. In that case, we return the original value.