strange initialization code in Python

Question

Wondering what below code mean? Does foo and goo initialized as a dictionary?

foo = [0] * 128
goo = [False] * 128

In all seriousness, this is when the interactive Python interpreter helps out a lot. If you say foo = [0] * 5 ; foo it will dutifully reply [0, 0, 0, 0, 0]. If you say type(foo) it will respond <class 'list'>, and so on. — msw
– msw, Commented Sep 12, 2015 at 2:52

Amber · Accepted Answer · 2015-09-12 00:38:08Z

3

Multiplying a list by an integer N creates a new list with the contents of the original list repeated N times.

[123] * 4 = [123, 123, 123, 123].

So [0] * 128 gives a 128-item list where each item is 0.

[False] * 128 gives a 128-item list where each item is False.

answered Sep 12, 2015 at 0:38

Amber

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3 Comments

thanks! Is there a way to know if [123] * 4 is a list type object?

Yes, [123] is a sequence of one element so * int can be applied yielding [123, 123, 123, 123].

@msw you can multiply a list of any length by an integer. [1, 2] * 3 = [1, 2, 1, 2, 1, 2].