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* array.c (rb_ary_combination): new method to give all combination
of elements from an array. [ruby-list:42671] * array.c (rb_ary_product): a new method to get all combinations of elements from two arrays. can be extended to combinations of n-arrays, e.g. a.product(b,c,d). anyone volunteer? * array.c (rb_ary_permutation): empty function body to calculate permutations of array elements. need volunteer. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@13568 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
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12
ChangeLog
12
ChangeLog
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@ -1,3 +1,15 @@
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Sat Sep 29 17:31:04 2007 Yukihiro Matsumoto <matz@ruby-lang.org>
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* array.c (rb_ary_combination): new method to give all combination
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of elements from an array. [ruby-list:42671]
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* array.c (rb_ary_product): a new method to get all combinations
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of elements from two arrays. can be extended to combinations of
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n-arrays, e.g. a.product(b,c,d). anyone volunteer?
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* array.c (rb_ary_permutation): empty function body to calculate
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permutations of array elements. need volunteer.
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Sat Sep 29 17:14:44 2007 Yukihiro Matsumoto <matz@ruby-lang.org>
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* marshal.c (r_leave): move proc invocation from r_entry() to
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140
array.c
140
array.c
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@ -2954,6 +2954,143 @@ rb_ary_cycle(VALUE ary)
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return Qnil;
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}
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static long
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perm_len(long n, long k)
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{
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long i, val = 1;
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while (n > k) {
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val *= n--;
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}
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return val;
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}
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/*
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* call-seq:
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* ary.permutation(n)
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*
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* Returns an array of all permutations of length <i>n</i> of
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* elements from <i>ary</i>].
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*
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* a = [1, 2, 3]
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* a.permutation(0).to_a #=> []
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* a.permutation(1).to_a #=> [[1],[2],[3]]
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* a.permutation(2).to_a #=> [[1,2],[1,3],[2,1],[2,3],[3,1],[3,2]]
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* a.permutation(3).to_a #=> [[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]
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* a.permutation(4).to_a #=> []
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*
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*/
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static VALUE
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rb_ary_permutation(VALUE ary, VALUE num)
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{
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/* TBD */
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}
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static long
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combi_len(long n, long k)
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{
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long i, val = 1;
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if (k*2 > n) k = n-k;
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if (k == 0) return 1;
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if (k < 0) return 0;
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val = 1;
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for (i=1; i <= k; i++,n--) {
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val *= n;
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val /= i;
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}
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return val;
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}
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/*
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* call-seq:
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* ary.combination(n)
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*
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* Returns an enumerator of all combinations of length <i>n</i> of
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* elements from <i>ary</i>].
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*
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* a = [1, 2, 3, 4]
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* a.combination(0).to_a #=> []
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* a.combination(1).to_a #=> [[1],[2],[3],[4]]
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* a.combination(2).to_a #=> [[1,2],[1,3],[1,4],[2,3],[2,4],[3,4]]
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* a.combination(3).to_a #=> [[1,2,3],[1,2,4],[1,3,4],[2,3,4]]
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* a.combination(4).to_a #=> [[1,2,3,4]]
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* a.combination(5).to_a #=> []
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*
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*/
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static VALUE
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rb_ary_combination(VALUE ary, VALUE num)
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{
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long n, i, len;
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RETURN_ENUMERATOR(ary, 1, &num);
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n = NUM2LONG(num);
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len = RARRAY_LEN(ary);
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if (n < 1 || len < n) {
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/* yield nothing */
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}
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else if (n == 0) {
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for (i = 0; i < len; i++) {
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rb_yield(rb_ary_new2(0));
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}
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}
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else if (n == 1) {
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for (i = 0; i < len; i++) {
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rb_yield(rb_ary_new3(1, RARRAY_PTR(ary)[i]));
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}
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}
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else {
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volatile VALUE tmp = rb_str_new(0, n*sizeof(long));
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long *stack = (long*)RSTRING_PTR(tmp);
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long nlen = combi_len(len, n);
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volatile VALUE cc = rb_ary_new2(n);
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VALUE *chosen = RARRAY_PTR(cc);
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long lev = 0;
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MEMZERO(stack, long, n);
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stack[0] = -1;
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for (i = 0; i < nlen; i++) {
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chosen[lev] = RARRAY_PTR(ary)[stack[lev+1]];
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for (lev++; lev < n; lev++) {
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chosen[lev] = RARRAY_PTR(ary)[stack[lev+1] = stack[lev]+1];
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}
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rb_yield(rb_ary_new4(n, chosen));
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do {
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stack[lev--]++;
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} while (lev && (stack[lev+1]+n == len+lev+1));
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}
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}
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return ary;
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}
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/*
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* call-seq:
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* ary.product(ary2)
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*
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* Returns an array of all combinations of elements from both arrays.
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*
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* [1,2,3].product([4,5]) #=> [[1,4],[1,5],[2,4],[2,5],[3,4],[3,5]]
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* [1,2].product([1,2]) #=> [[1,1],[1,2],[2,1],[2,2]]
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*
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*/
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static VALUE
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rb_ary_product(VALUE ary, VALUE a2)
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{
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VALUE result = rb_ary_new2(RARRAY_LEN(ary));
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long i, j;
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for (i=0; i<RARRAY_LEN(ary); i++) {
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for (j=0; j<RARRAY_LEN(a2); j++) {
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rb_ary_push(result, rb_ary_new3(2, rb_ary_entry(ary, i),
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rb_ary_entry(a2, j)));
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}
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}
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return result;
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}
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/* Arrays are ordered, integer-indexed collections of any object.
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* Array indexing starts at 0, as in C or Java. A negative index is
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* assumed to be relative to the end of the array---that is, an index of -1
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@ -3052,6 +3189,9 @@ Init_Array(void)
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rb_define_method(rb_cArray, "shuffle", rb_ary_shuffle, 0);
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rb_define_method(rb_cArray, "choice", rb_ary_choice, 0);
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rb_define_method(rb_cArray, "cycle", rb_ary_cycle, 0);
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/* rb_define_method(rb_cArray, "permutation", rb_ary_permutation, 1); */
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rb_define_method(rb_cArray, "combination", rb_ary_combination, 1);
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rb_define_method(rb_cArray, "product", rb_ary_product, 1);
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id_cmp = rb_intern("<=>");
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}
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2
string.c
2
string.c
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@ -2872,6 +2872,7 @@ rb_str_inspect(VALUE str)
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char *p, *pend;
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VALUE result = rb_str_buf_new2("");
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rb_enc_associate(result, enc);
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str_cat_char(result, '"', enc);
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p = RSTRING_PTR(str); pend = RSTRING_END(str);
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while (p < pend) {
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@ -2928,7 +2929,6 @@ rb_str_inspect(VALUE str)
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str_cat_char(result, '"', enc);
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OBJ_INFECT(result, str);
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rb_enc_associate(result, enc);
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return result;
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}
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@ -1177,4 +1177,26 @@ class TestArray < Test::Unit::TestCase
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assert_equal(@cls[1,2], @cls[1, 2] | @cls[1, 2])
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end
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# def test_permutation
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# assert_equal(@cls[], @cls[1,2,3].permutation(0).to_a)
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# assert_equal(@cls[[1],[2],[3]], @cls[1,2,3].permutation(1).to_a)
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# assert_equal(@cls[[1,2],[1,3],[2,1],[2,3],[3,1],[3,2]], @cls[1,2,3].permutation(2).to_a)
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# assert_equal(@cls[[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]], @cls[1,2,3].permutation(3).to_a)
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# assert_equal(@cls[], @cls[1,2,3].permutation(4).to_a)
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# end
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def test_combination
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assert_equal(@cls[], @cls[1,2,3,4].combination(0).to_a)
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assert_equal(@cls[[1],[2],[3],[4]], @cls[1,2,3,4].combination(1).to_a)
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assert_equal(@cls[[1,2],[1,3],[1,4],[2,3],[2,4],[3,4]], @cls[1,2,3,4].combination(2).to_a)
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assert_equal(@cls[[1,2,3],[1,2,4],[1,3,4],[2,3,4]], @cls[1,2,3,4].combination(3).to_a)
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assert_equal(@cls[[1,2,3,4]], @cls[1,2,3,4].combination(4).to_a)
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assert_equal(@cls[], @cls[1,2,3,4].combination(5).to_a)
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end
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def test_product
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assert_equal(@cls[[1,4],[1,5],[2,4],[2,5],[3,4],[3,5]],
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@cls[1,2,3].product([4,5]))
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assert_equal(@cls[[1,1],[1,2],[2,1],[2,2]], @cls[1,2].product([1,2]))
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end
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end
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