my_empty_list = [] print(f"empty list: {my_empty_list}, type: {type(my_empty_list)}") empty list: [], type: <class 'list'>
list_of_ints = [1, 2, 6, 7] list_of_misc = [0.2, 5, "Python", "is", "still fun", "!"] print(f"lengths: {len(list_of_ints)} and {len(list_of_misc)}") lengths: 4 and 6
my_list = ["Python", "is", "still", "cool"] print(my_list[0]) print(my_list[3]) Python cool
coordinates = [[12.0, 13.3], [0.6, 18.0], [88.0, 1.1]] # two dimensional print(f"first coordinate: {coordinates[0]}") print(f"second element of first coordinate: {coordinates[0][1]}") first coordinate: [12.0, 13.3] second element of first coordinate: 13.3
my_list = [0, 1, 2, 3, 4, 5] my_list[0] = 99 print(my_list) # remove first value del my_list[0] print(my_list) [99, 1, 2, 3, 4, 5] [1, 2, 3, 4, 5]
languages = ["Java", "C++", "Go", "Python", "JavaScript"] if "Python" in languages: print("Python is there!") Python is there!
if 6 not in [1, 2, 3, 7]: print("number 6 is not present") number 6 is not present
original = [1, 2, 3] modified = original modified[0] = 99 print(f"original: {original}, modified: {modified}") original: [99, 2, 3], modified: [99, 2, 3]
You can get around this by creating new list:
original = [1, 2, 3] modified = list(original) # Note list() # Alternatively, you can use copy method # modified = original.copy() modified[0] = 99 print(f"original: {original}, modified: {modified}") original: [1, 2, 3], modified: [99, 2, 3]
list.append()¶my_list = [1] my_list.append("ham") print(my_list) [1, 'ham']
list.remove()¶my_list = ["Python", "is", "sometimes", "fun"] my_list.remove("sometimes") print(my_list) # If you are not sure that the value is in list, better to check first: if "Java" in my_list: my_list.remove("Java") else: print("Java is not part of this story.") ['Python', 'is', 'fun'] Java is not part of this story.
list.sort()¶numbers = [8, 1, 6, 5, 10] numbers.sort() print(f"numbers: {numbers}") numbers.sort(reverse=True) print(f"numbers reversed: {numbers}") words = ["this", "is", "a", "list", "of", "words"] words.sort() print(f"words: {words}") numbers: [1, 5, 6, 8, 10] numbers reversed: [10, 8, 6, 5, 1] words: ['a', 'is', 'list', 'of', 'this', 'words']
sorted(list)¶While list.sort() sorts the list in-place, sorted(list) returns a new list and leaves the original untouched:
numbers = [8, 1, 6, 5, 10] sorted_numbers = sorted(numbers) print(f"{numbers=}, {sorted_numbers=}") numbers=[8, 1, 6, 5, 10], sorted_numbers=[1, 5, 6, 8, 10]
list.extend()¶first_list = ["beef", "ham"] second_list = ["potatoes", 1, 3] first_list.extend(second_list) print(f"{first_list=}, {second_list=}") first_list=['beef', 'ham', 'potatoes', 1, 3], second_list=['potatoes', 1, 3]
Alternatively you can also extend lists by summing them:
first = [1, 2, 3] second = [4, 5] first += second # same as: first = first + second print(f"{first=}") first=[1, 2, 3, 4, 5]
list.reverse()¶my_list = ["a", "b", "ham"] my_list.reverse() print(my_list) ['ham', 'b', 'a']