Python List Comprehension

List comprehension offers a shorter syntax when you want to create a new list based on the values of an existing list.

Syntax

newlist = [expression for item in iterable if condition == True]

Example

Based on a list of fruits, you want a new list, containing only the fruits with the letter "a" in the name.

Without list comprehension:

fruits = ["apple", "banana", "cherry", "kiwi", "mango"]
newlist = []

for x in fruits:
  if "a" in x:
    newlist.append(x)

With list comprehension:

fruits = ["apple", "banana", "cherry", "kiwi", "mango"]
newlist = [x for x in fruits if "a" in x]

More Examples

• No condition: [x for x in fruits]
• Iterable: [x for x in range(10)]
• Expression: [x.upper() for x in fruits]
• If-Else: [x if x != "banana" else "orange" for x in fruits]

Readability

List comprehension is very "Pythonic" and clean, but don't make them too complex or they become hard to read!