Cartesian product of two or more lists: Difference between revisions

=={{header|UNIX Shell}}==

The UNIX shells don't allow passing or returning arrays from functions (other than pass-by-name shenanigans), but as pointed out in the Perl entry, wildcard brace expansion (in bash, ksh, zsh) does a Cartesian product if there's more than one set of alternatives. It doesn't handle the empty-list case (an empty brace expansion item is treated as a single item that is equal to the empty string), but otherwise it works:

$ printf '%s' "("{1,2},{3,4}")"; printf '\n'

(1,3)(1,4)(2,3)(2,4)

$ printf '%s' "("{3,4},{1,2}")"; printf '\n'

(3,1)(3,2)(4,1)(4,2)

More than two lists is not a problem:

$ printf '%s\n' "("{1776,1789},{7,12},{4,14,23},{0,1}")"

(1776,7,4,0)

(1776,7,4,1)

(1776,7,14,0)

(1776,7,14,1)

(1776,7,23,0)

(1776,7,23,1)

(1776,12,4,0)

(1776,12,4,1)

(1776,12,14,0)

(1776,12,14,1)

(1776,12,23,0)

(1776,12,23,1)

(1789,7,4,0)

(1789,7,4,1)

(1789,7,14,0)

(1789,7,14,1)

(1789,7,23,0)

(1789,7,23,1)

(1789,12,4,0)

(1789,12,4,1)

(1789,12,14,0)

(1789,12,14,1)

(1789,12,23,0)

(1789,12,23,1)

$ printf '%s\n' "("{1,2,3},30,{500,100}")"

(1,30,500)

(1,30,100)

(2,30,500)

(2,30,100)

(3,30,500)

(3,30,100)