diff options
author | matz <matz@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2008-08-11 10:00:47 +0000 |
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committer | matz <matz@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2008-08-11 10:00:47 +0000 |
commit | 9295fd4b5978dbb51aabc3981a245aacd7ffcac5 (patch) | |
tree | ed93074b4e938f55f06c2fa5d8e4f21eb77faf81 | |
parent | 130e72025328746295d2efe45a6856f8d9ff154b (diff) |
* array.c (rb_ary_sample): rename #choice to #sample. in
addition, sample takes optional argument, a la #first.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@18494 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
-rw-r--r-- | ChangeLog | 5 | ||||
-rw-r--r-- | array.c | 45 | ||||
-rw-r--r-- | test/ruby/test_array.rb | 8 |
3 files changed, 47 insertions, 11 deletions
@@ -1,3 +1,8 @@ +Mon Aug 11 18:57:38 2008 Yukihiro Matsumoto <matz@ruby-lang.org> + + * array.c (rb_ary_sample): rename #choice to #sample. in + addition, sample takes optional argument, a la #first. + Mon Aug 11 18:28:02 2008 Narihiro Nakamura <authorNari@gmail.com> * gc.c: added GC::Profiler. @@ -2998,21 +2998,48 @@ rb_ary_shuffle(VALUE ary) /* * call-seq: - * array.choice -> obj + * array.sample -> obj + * array.sample(n) -> an_array + * + * Choose a random element, or the random +n+ elements, fron the array. + * If the array is empty, the first form returns <code>nil</code>, and the + * second form returns an empty array. * - * Choose a random element from an array. */ static VALUE -rb_ary_choice(VALUE ary) +rb_ary_sample(int argc, VALUE *argv, VALUE ary) { - long i, j; + VALUE nv, result; + int n, len, i, j; - i = RARRAY_LEN(ary); - if (i == 0) return Qnil; - j = rb_genrand_real()*i; - return RARRAY_PTR(ary)[j]; + len = RARRAY_LEN(ary); + if (argc == 0) { + if (len == 0) return Qnil; + i = rb_genrand_real()*len; + return RARRAY_PTR(ary)[i]; + } + rb_scan_args(argc, argv, "1", &nv); + if (len == 0) return rb_ary_new2(0); + n = NUM2INT(nv); + result = rb_ary_new2(n); + for (i=0; i<n; i++) { + retry: + j = rb_genrand_real()*len; + nv = LONG2NUM(j); + for (j=0; j<i; j++) { + if (RARRAY_PTR(result)[j] == nv) + goto retry; + } + RARRAY_PTR(result)[i] = nv; + ARY_SET_LEN(result, i+1); + } + for (i=0; i<n; i++) { + nv = RARRAY_PTR(result)[i]; + RARRAY_PTR(result)[i] = RARRAY_PTR(ary)[NUM2LONG(nv)]; + } + return result; } @@ -3526,7 +3553,7 @@ Init_Array(void) rb_define_method(rb_cArray, "count", rb_ary_count, -1); rb_define_method(rb_cArray, "shuffle!", rb_ary_shuffle_bang, 0); 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, "sample", rb_ary_sample, -1); rb_define_method(rb_cArray, "cycle", rb_ary_cycle, -1); rb_define_method(rb_cArray, "permutation", rb_ary_permutation, -1); rb_define_method(rb_cArray, "combination", rb_ary_combination, 1); diff --git a/test/ruby/test_array.rb b/test/ruby/test_array.rb index 42553d1932..7258b22a5b 100644 --- a/test/ruby/test_array.rb +++ b/test/ruby/test_array.rb @@ -1518,9 +1518,13 @@ class TestArray < Test::Unit::TestCase end end - def test_choice + def test_sample 100.times do - assert([0, 1, 2].include?([2, 1, 0].choice)) + assert([0, 1, 2].include?([2, 1, 0].sample)) + samples = [2, 1, 0].sample(2) + samples.each{|sample| + assert([0, 1, 2].include?(sample)) + } end end |