<s>[INST] How to initialize a two-dimensional array in Python? I'm beginning python and I'm trying to use a two-dimensional list, that I initially fill up with the same variable in every place. I came up with this:
def initialize_twodlist(foo):
    twod_list = []
    new = []
    for i in range (0, 10):
        for j in range (0, 10):
            new.append(foo)
        twod_list.append(new)
        new = []

It gives the desired result, but feels like a workaround. Is there an easier/shorter/more elegant way to do this?
 [/INST] A pattern that often came up in Python was
bar = []
for item in some_iterable:
    bar.append(SOME EXPRESSION)

which helped motivate the introduction of list comprehensions, which convert that snippet to
bar = [SOME EXPRESSION for item in some_iterable]

which is shorter and sometimes clearer. Usually you get in the habit of recognizing these and often replacing loops with comprehensions.
Your code follows this pattern twice
twod_list = []                                       \                      
for i in range (0, 10):                               \
    new = []                  \ can be replaced        } this too
    for j in range (0, 10):    } with a list          /
        new.append(foo)       / comprehension        /
    twod_list.append(new)                           /

 </s>