Anonymous user
Permutations: Difference between revisions
→{{header|Mathematica}}: added version defining permutations from scratch
(→{{header|Mercury}}: output) |
(→{{header|Mathematica}}: added version defining permutations from scratch) |
||
Line 3,790:
=={{header|Mathematica}}==
Version from scratch:
<lang Mathematica>
(***Standard list functions:*)
fold[f_, x_, {}] := x
fold[f_, x_, {h_, t___}] := fold[f, f[x, h], {t}]
insert[L_, x_, n_] := Join[L[[;; n - 1]], {x}, L[[n ;;]]]
(***Generate all permutations of a set S:*)
permutations[S_] :=
fold[Join @@ (Function[{L},
Table[insert[L, #2, k + 1], {k, 0, Length[L]}]] /@ #1) &, {{}},
S]
</lang>
Built-in version:
<lang Mathematica>Permutations[{1,2,3,4}]</lang>
{{out}}
| |||