How to initialize a two-dimensional array (list of lists, if not using NumPy) in Python?

Question

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?

Just a small (or significant, depending on who is watching) nitpick : lists are not arrays. If you want arrays, use numpy. — Arnab Datta
– Arnab Datta, Commented Apr 22, 2012 at 1:10
This question is similar: it discusses the initialization of multidimensional arrays in Python. — Anderson Green
– Anderson Green, Commented Apr 6, 2013 at 3:35
@ArnabDatta How would you initialize a multidimensional array in numpy, then? — Anderson Green
– Anderson Green, Commented Apr 6, 2013 at 16:17
You can arrange data in an array like structure in default Python but it's not nearly as efficient or useful as a NumPy array. Especially if you want to deal with large data sets. Here's some documentation docs.scipy.org/doc/numpy-1.10.1/user/basics.creation.html — jmdeamer
– jmdeamer, Commented May 16, 2016 at 21:08

Paul Roub · Accepted Answer · 2017-10-19 22:43:20Z

-5

from random import randint
l = []

for i in range(10):
    k=[]
    for j in range(10):
        a= randint(1,100)
        k.append(a)

    l.append(k)




print(l)
print(max(l[2]))

b = []
for i in range(10):
    a = l[i][5]
    b.append(a)

print(min(b))

edited Oct 19, 2017 at 22:43

Paul Roub

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answered Oct 19, 2017 at 22:41

KANDARP JAYESH SHAH

1

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2 Comments

whackamadoodle3000 Over a year ago

Please add some text describing what your code does.

Massimiliano Kraus Over a year ago

Usually it's better to explain a solution instead of just posting some rows of anonymous code. You can read How do I write a good answer, and also Explaining entirely code-based answers.

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