[FIXED] zip list with a single element

Issue

I have a list of some elements, e.g. [1, 2, 3, 4] and a single object, e.g. 'a'. I want to produce a list of tuples with the elements of the list in the first position and the single object in the second position: [(1, 'a'), (2, 'a'), (3, 'a'), (4, 'a')].

I could do it with zip like this:

def zip_with_scalar(l, o): # l - the list; o - the object
    return list(zip(l, [o] * len(l)))

However, this gives me a feeling of creating and unnecessary list of repeating element.

Another possibility is

def zip_with_scalar(l, o):
    return [(i, o) for i in l]

which is very clean and pythonic indeed, but here I do the whole thing "manually". In Haskell I would do something like

zipWithScalar l o = zip l $ repeat o

Is there any built-in function or trick, either for the zipping with scalar or for something that would enable me to use ordinary zip, i.e. sort-of infinite list?

Solution

This is the cloest to your Haskell solution:

import itertools

def zip_with_scalar(l, o):
    return zip(l, itertools.repeat(o))

You could also use generators, which avoid creating a list like comprehensions do:

def zip_with_scalar(l, o):
    return ((i, o) for i in l)

Answered By - kirbyfan64sos