How to multiply a list of text by a list of integers and get one long list of text?

Question

This is for Python 3. I have two lists:

lista = [\'foo\', \'bar\']
listb = [2, 3]

I\'m trying to get:

newlist = [\'foo\', \'foo         


        

Answer 1

You can use list comprehension with the following one liner:

new_list = [x for n,x in zip(listb,lista) for _ in range(n)]

The code works as follows: first we generate a zip(listb,lista) which generates tuples of (2,'foo'), (3,'bar'), ... Now for each of these tuples we have a second for loop that iterates n times (for _ in range(n)) and thus we add x that many times to the list.

The _ is a variable that is usually used to denote that the value _ carries is not important: it is only used because we need a variable in the for loop to force iteration.