Joel wrote:
> Finally, I'd considered handling the structure-traversing issues
separately from the data-manipulation issues, by defining (this version is
VERY quick and dirty):
>
> >> transpose: function [b [block!]] [w i s r] [
> [ r: make block! w: accum length? b/1 map b :length? :min
> [ repeat i w [
> [ s: make block! length? b
> [ foreach c b [append/only s c/:i]
> [ append/only r s
> [ ]
> [ r
> [ ]
> >> transpose [[1 2 3 4 5] ["a" "b" "c" "d" "e"]]
> == [[1 "a"] [2 "b"] [3 "c"] [4 "d"] [5 "e"]]
> >> transpose [[1 2 3] [14 15 16] [27 28 29]]
> == [[1 14 27] [2 15 28] [3 16 29]]
I've cleaned it up a bit:
[
Rebol [
Name: 'Transpose
Title: "Transpose"
File: %"Transpose.r"
Author: "Andrew Martin"
eMail: [EMAIL PROTECTED]
Date: 5/October/2000
Enhancement: 'Transpose
Acknowledgements: "Joel Neely"
Example: [
transpose [[1 2 3 4 5] ["a" "b" "c" "d" "e"]]
; [[1 "a"] [2 "b"] [3 "c"] [4 "d"] [5 "e"]]
transpose [[1 2 3] [14 15 16] [27 28 29]]
; [[1 14 27] [2 15 28] [3 16 29]]
]
]
Transpose: function [
[catch]
"Transposes Matrices"
Matrix [block!]
][
Results Width Height Column
][
Results: make block! Width: length? Matrix/1
Height: length? Matrix
repeat Index Width [
Column: make block! Width
foreach Row Matrix [
insert/only tail Column Row/:Index
]
insert/only tail Results Column
]
Results
]
]
>> transpose [[1 2 3 4 5] ["a" "b" "c" "d" "e"]]
== [[1 "a"] [2 "b"] [3 "c"] [4 "d"] [5 "e"]]
>> ; [[1 "a"] [2 "b"] [3 "c"] [4 "d"] [5 "e"]]
>> transpose [[1 2 3] [14 15 16] [27 28 29]]
== [[1 14 27] [2 15 28] [3 16 29]]
>> ; [[1 14 27] [2 15 28] [3 16 29]]
> Critiques/comments/debugging welcome!
I totally agree. :-)
Andrew Martin
ICQ: 26227169
http://members.nbci.com/AndrewMartin/
-><-
