Generating a list of constants with a comprehension?

Question

I was wondering how I would generate a list of constants with a python comprehension?

For instance, if I wanted to generate a list of 100 number 5s, how would I do this?

I'm having trouble understanding this because the way I keep track of the number of elements in the list is distinct from what I would like to output.

Answer 1

For immutable values, just multiply the list:

count = 100
[5] * count

For mutable values, use a list comprehension:

count = 100
[{'foo': 5} for _ in xrange(count)]

The _ name here is just a convention; it means we are ignoring the loop target name in the loop itself.

Answer 2

You can do:

my_list = [5 for _ in xrange(100)]

You can also do:

import itertools
my_list = list(itertools.repeat(5, 100))