31 lines
929 B
Nix
31 lines
929 B
Nix
|
{ ... }:
|
||
|
|
|
||
|
|
{
|
||
|
|
/* For a list of length n that consists of lists of length m,
|
||
|
|
return a list of length m containing lists of length n
|
||
|
|
so that
|
||
|
|
|
||
|
|
builtins.elemAt (builtins.elemAt orig a) b
|
||
|
|
== builtins.elemAt (builtins.elemAt transposed b) a
|
||
|
|
|
||
|
|
Essentially, if you think of the nested list as an array with two
|
||
|
|
dimensions, the two index axes are swapped.
|
||
|
|
|
||
|
|
The length of the inner lists m is determined based on the first element
|
||
|
|
and assumed to be used for all other lists. Malformed input data may
|
||
|
|
cause the function to crash or lose data.
|
||
|
|
|
||
|
|
Type: <n>[ <m>[ ] ] -> <m>[ <n>[ ] ]
|
||
|
|
*/
|
||
|
|
transpose = list:
|
||
|
|
let
|
||
|
|
innerLength = builtins.length (builtins.head list);
|
||
|
|
outerLength = builtins.length list;
|
||
|
|
in
|
||
|
|
builtins.genList
|
||
|
|
(inner: builtins.genList
|
||
|
|
(outer: builtins.elemAt (builtins.elemAt list outer) inner)
|
||
|
|
outerLength)
|
||
|
|
innerLength;
|
||
|
|
}
|