feat(list): adding list:transpose

Author: SuperFola

List.ark

@@ -674,3 +674,29 @@
     (if (>= (+ _i _size) (len _L))
       (set _i (len _L)))
     (set _i (+ 1 _i)) }) }))
+
+# @brief Transpose a list of lists or list of strings
+# @details The original list is not modified. Each element should have the same length
+# @param _L list of lists/strings to transpose
+# =begin
+# (let data [[1 2 3] [4 5 6] [7 8 9])
+# (print (list:transpose data))  # [[1 4 7] [2 5 8] [3 6 9]]
+# =end
+# @author https://github.com/SuperFola
+(let transpose (fun (_L) {
+  (mut _output [])
+  (mut _i 0)
+  (let _width (len (head _L)))
+  (let _height (len _L))
+
+  (while (< _i _width) {
+    (mut _column [])
+    (mut _k 0)
+    (while (< _k _height) {
+      (append! _column (@@ _L _k _i))
+      (set _k (+ _k 1)) })
+
+    (append! _output _column)
+    (set _i (+ 1 _i)) })
+  _output }))
+

tests/list-tests.ark

@@ -188,4 +188,13 @@
                 (test:eq (@ l 1) (+ 1 i))
                 (set i (+ 1 i))
                 (test:eq 2 (len l)) }))
-        (test:eq i 4) }) })
+        (test:eq i 4) })
+
+    (test:case "transpose" {
+        (test:eq (list:transpose [[1 2 3] [4 5 6] [7 8 9]]) [[1 4 7] [2 5 8] [3 6 9]])
+        (let data ["123 328  51" " 45 64  387"])
+        (test:eq (list:transpose data) [["1" " "] ["2" "4"] ["3" "5"] [" " " "] ["3" "6"] ["2" "4"] ["8" " "] [" " " "] [" " "3"] ["5" "8"] ["1" "7"]])
+        (test:eq (list:transpose (list:transpose zipped)) zipped)
+        (test:eq (list:transpose [[]]) [])
+        (test:eq (list:transpose [[1]]) [[1]]) }) })
+