Permutations: Difference between revisions

m (→‎{{header|Wren}}: Minor tidy)
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This follows the Go language non-recursive example, but is not limited to integers, or even to numbers.
 
<syntaxhighlight lang="langur">val .factorial = ffn(.x) if(.x < 2: 1; .x x* self(.x - 1))
{{works with|langur|0.10}}
Prior to 0.10, multi-variable declaration/assignment would use parentheses around variable names and values. 0.10 also parses the increment section of a for loop as a multi-variable assignment, not as a list of assignments.
 
val .permute = ffn(.arrlist) {
<syntaxhighlight lang="langur">val .factorial = f if(.x < 2: 1; .x x self(.x - 1))
if .list is not isArray(.arr)list: throw "expected arraylist"
 
val .permute = f(.arr) {
if not isArray(.arr): throw "expected array"
 
val .limit = 10
if len(.arrlist) > .limit: throw $"permutation limit exceeded (currently \.limit;)"
 
var .elements = .arrlist
var .ordinals = pseries len .elements
 
Line 5,708 ⟶ 5,705:
var .i, .j
 
for[.p=[.arrlist]] of .factorial(len .arrlist)-1 {
.i = .n - 1
.j = .n
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for .e in .permute([1, 3.14, 7]) {
writeln .e
}
}</syntaxhighlight>
 
{{out}}
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st> 'Abc' permutations contents
('bcA' 'cbA' 'cAb' 'Acb' 'bAc' 'Abc' )
</syntaxhighlight>
 
=={{header|Standard ML}}==
<syntaxhighlight lang="sml">
fun interleave x [] = [[x]]
| interleave x (y::ys) = (x::y::ys) :: (List.map (fn a => y::a) (interleave x ys))
 
fun perms [] = [[]]
| perms (x::xs) = List.concat (List.map (interleave x) (perms xs))
</syntaxhighlight>
 
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