*
) is overloaded for lists to serve as
a repetition operator. The result of applying repetition to a list is a
single list, with the elements of the original list repeated as many times
as you specify:
>>> ['a','b','c'] * 4 ['a', 'b', 'c', 'a', 'b', 'c', 'a', 'b', 'c', 'a', 'b', 'c']Special care needs to be taken when the list being repeated contains only one element. Note that the expression 3 * 5 is a simple numeric computation, while
>>> 3 * [5] [5, 5, 5]produces a list containing the element 5 repeated 3 times. By surrounding a list to be repeated with an extra set of square brackets, lists consisting of other lists can be constructed:
>>> littlelist = [1,2,3] >>> 3 * littlelist [1, 2, 3, 1, 2, 3, 1, 2, 3] >>> 3 * [littlelist] [[1, 2, 3], [1, 2, 3], [1, 2, 3]]