e$B1sF#$H?=$7$^$9!#e(B
Array#permutation e$B$O%G%U%)%k%H$GA4MWAG$N=gNse(B (e$B$D$^$jCV49e(B)
e$B$r7W;;$9$k$He(B
e$B$$$$$H;W$$$^$9!#$I$&$G$7$g$&$+!#e(B
a = [1,2,3]
a.permutation.to_a
#=> [[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]
Index: array.c
— array.c (revision 13961)
+++ array.c (working copy)
@@ -3001,11 +3001,14 @@
/*
- call-seq:
-
-
ary.permutation { |p| block } -> array
-
-
-
ary.permutation -> enumerator -
ary.permutation(n) { |p| block } -> array -
ary.permutation(n) -> enumerator - When invoked with a block, yield all permutations of length n
- of the elements of ary, then return the array itself.
-
-
- If n is not specified, yield all permutations of all
elements. - The implementation makes no guarantees about the order in which
- the permutations are yielded.
- If n is not specified, yield all permutations of all
@@ -3013,6 +3016,7 @@
*
- Examples:
-
a = [1, 2, 3]
-
-
a.permutation.to_a #=>
-
[[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]
-
a.permutation(1).to_a #=> [[1],[2],[3]] -
a.permutation(2).to_a #=> [[1,2],[1,3],[2,1],[2,3],[3,1],[3,2]] -
a.permutation(3).to_a #=>
[[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]
@@ -3021,13 +3025,15 @@
*/
static VALUE
-rb_ary_permutation(VALUE ary, VALUE num)
+rb_ary_permutation(int argc, VALUE *argv, VALUE ary)
{
- VALUE num;
long r, n, i;
- RETURN_ENUMERATOR(ary, 1, &num); /* Return enumerator if no block
*/ - r = NUM2LONG(num); /* Permutation size from argument
*/ - n = RARRAY_LEN(ary); /* Array length */
-
RETURN_ENUMERATOR(ary, argc, argv); /* Return enumerator if no
block */ -
n = RARRAY_LEN(ary); /* Array length */
-
rb_scan_args(argc, argv, “01”, &num);
-
r = NIL_P(num) ? n : NUM2LONG(num); /* Permutation size from
argument */if (r < 0 || n < r) {
/* no permutations: yield nothing */
@@ -3310,7 +3316,7 @@
rb_define_method(rb_cArray, “shuffle”, rb_ary_shuffle, 0);
rb_define_method(rb_cArray, “choice”, rb_ary_choice, 0);
rb_define_method(rb_cArray, “cycle”, rb_ary_cycle, 0);
- rb_define_method(rb_cArray, “permutation”, rb_ary_permutation, 1);
- rb_define_method(rb_cArray, “permutation”, rb_ary_permutation, -1);
rb_define_method(rb_cArray, “combination”, rb_ary_combination, 1);
rb_define_method(rb_cArray, “product”, rb_ary_product, -1);