Create list/matrix with row for each value in two lists

Question

Say you have 2 lists of unique values, how can you create a list/dataframe/array with a record for each value.

list_1 = [1, 2, 3, 4]
list_2 = ['one', 'two', 'three', 'four']

expected = [
    [1, 'one'],
    [2, 'one'],
    [3, 'one'],
    [4, 'one'],
    ...
    [1, 'four'],
    [2, 'four'],
    [3, 'four'],
    [4, 'four']
]

I recommend using the Pandorable / Numpythonic solution [here](https://stackoverflow.com/a/25636395/9209546) in the dup. — jpp, Sep 28 '18 at 18:06

score 1 · Accepted Answer · answered Sep 28 '18 at 18:04

You could use list comprehension:

[[i,j] for i in list_1 for j in list_2]

Output:

[[1, 'one'],
 [1, 'two'],
 [1, 'three'],
 [1, 'four'],
 [2, 'one'],
 [2, 'two'],
 [2, 'three'],
 [2, 'four'],
 [3, 'one'],
 [3, 'two'],
 [3, 'three'],
 [3, 'four'],
 [4, 'one'],
 [4, 'two'],
 [4, 'three'],
 [4, 'four']]

Or you could use itertools.product to get a list of tuples:

import itertools
list(itertools.product(list_1, list_2))

Output:

[(1, 'one'),
 (1, 'two'),
 (1, 'three'),
 (1, 'four'),
 (2, 'one'),
 (2, 'two'),
 (2, 'three'),
 (2, 'four'),
 (3, 'one'),
 (3, 'two'),
 (3, 'three'),
 (3, 'four'),
 (4, 'one'),
 (4, 'two'),
 (4, 'three'),
 (4, 'four')]

Create list/matrix with row for each value in two lists

1 Answers1