Course Content
Python Data Structures
Python Data Structures
List Comprehensions
List comprehensions are a powerful way to create new lists by combining loops and optional conditions into a single, concise statement. They provide a more Pythonic way to perform operations on lists, making your code cleaner and easier to read.
Creating a New List: Traditional for Loop vs. List Comprehension
Let's start with a simple example. You have a travel_wishlist containing cities you want to visit, each represented as a nested list with its name, country, and trip cost.
So, you need a list with city names only, without countries and trip costs.
For that task you can use for loop:
travel_wishlist = [ ["Paris", "France", 2000], ["Tokyo", "Japan", 3000], ["New York", "USA", 2500], ["Kyoto", "Japan", 1500], ["Sydney", "Australia", 4000] ] city_names = [] # a new empty list for city in travel_wishlist: city_names.append(city[0]) print(city_names) # Output: ['Paris', 'Tokyo', 'New York', 'Kyoto', 'Sydney']
Here, the list comprehension does the same job in a single line, making it concise and readable.
travel_wishlist = [ ["Paris", "France", 2000], ["Tokyo", "Japan", 3000], ["New York", "USA", 2500], ["Kyoto", "Japan", 1500], ["Sydney", "Australia", 4000] ] city_names = [city[0] for city in travel_wishlist] print(city_names) # Output: ['Paris', 'Tokyo', 'New York', 'Kyoto', 'Sydney']
The list comprehension combines the loop and the condition into a single line, making the code easier to understand at a glance.
Swipe to show code editor
You are managing a travel wishlist, and you need to create a new list that contains only the trip costs (the third element) from each destination in the wishlist.
Note
Switch to desktop for real-world practiceContinue from where you are using one of the options belowThanks for your feedback!
List Comprehensions
List comprehensions are a powerful way to create new lists by combining loops and optional conditions into a single, concise statement. They provide a more Pythonic way to perform operations on lists, making your code cleaner and easier to read.
Creating a New List: Traditional for Loop vs. List Comprehension
Let's start with a simple example. You have a travel_wishlist containing cities you want to visit, each represented as a nested list with its name, country, and trip cost.
So, you need a list with city names only, without countries and trip costs.
For that task you can use for loop:
travel_wishlist = [ ["Paris", "France", 2000], ["Tokyo", "Japan", 3000], ["New York", "USA", 2500], ["Kyoto", "Japan", 1500], ["Sydney", "Australia", 4000] ] city_names = [] # a new empty list for city in travel_wishlist: city_names.append(city[0]) print(city_names) # Output: ['Paris', 'Tokyo', 'New York', 'Kyoto', 'Sydney']
Here, the list comprehension does the same job in a single line, making it concise and readable.
travel_wishlist = [ ["Paris", "France", 2000], ["Tokyo", "Japan", 3000], ["New York", "USA", 2500], ["Kyoto", "Japan", 1500], ["Sydney", "Australia", 4000] ] city_names = [city[0] for city in travel_wishlist] print(city_names) # Output: ['Paris', 'Tokyo', 'New York', 'Kyoto', 'Sydney']
The list comprehension combines the loop and the condition into a single line, making the code easier to understand at a glance.
Swipe to show code editor
You are managing a travel wishlist, and you need to create a new list that contains only the trip costs (the third element) from each destination in the wishlist.
Note
Switch to desktop for real-world practiceContinue from where you are using one of the options belowThanks for your feedback!
Switch to desktop for real-world practiceContinue from where you are using one of the options below