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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']