All categories

    Lists

    Creating, indexing, slicing, and comprehensions.

    01Create and index a list

    main.py
    nums = [10, 20, 30, 40, 50]
    print(nums[0])
    print(nums[-1])
    print(len(nums))
    Output
    10
    50
    5

    02Slicing

    main.py
    xs = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
    print(xs[2:6])
    print(xs[:4])
    print(xs[5:])
    print(xs[::2])
    print(xs[::-1])
    Output
    [2, 3, 4, 5]
    [0, 1, 2, 3]
    [5, 6, 7, 8, 9]
    [0, 2, 4, 6, 8]
    [9, 8, 7, 6, 5, 4, 3, 2, 1, 0]

    03Append, insert, remove

    main.py
    items = ["a", "b", "c"]
    items.append("d")
    items.insert(1, "x")
    items.remove("b")
    print(items)
    Output
    ['a', 'x', 'c', 'd']

    04List comprehension

    main.py
    squares = [n * n for n in range(1, 6)]
    evens = [n for n in range(10) if n % 2 == 0]
    print(squares)
    print(evens)
    Output
    [1, 4, 9, 16, 25]
    [0, 2, 4, 6, 8]

    05Sort and reverse

    main.py
    nums = [4, 1, 9, 2, 7]
    print(sorted(nums))
    print(sorted(nums, reverse=True))
    nums.sort()
    print(nums)
    Output
    [1, 2, 4, 7, 9]
    [9, 7, 4, 2, 1]
    [1, 2, 4, 7, 9]