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[DOC] Tweaks for Array#repeated_combination (#11839)

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Burdette Lamar 2024-10-10 10:15:17 -05:00 committed by GitHub
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Notes: git 2024-10-10 15:15:35 +00:00 
Merged-By: peterzhu2118 <peter@peterzhu.ca>
1 changed files with 22 additions and 46 deletions
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array.c
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@ -7365,65 +7365,41 @@ rb_ary_repeated_combination_size(VALUE ary, VALUE args, VALUE eobj)
/*
* call-seq:
* array.repeated_combination(n) {|combination| ... } -> self
* array.repeated_combination(n) -> new_enumerator
* repeated_combination(size) {|combination| ... } -> self
* repeated_combination(size) -> new_enumerator
*
* Calls the block with each repeated combination of length +n+ of the elements of +self+;
* each combination is an +Array+;
* With a block given, calls the block with each repeated combination of length +size+
* of the elements of +self+;
* each combination is an array;
* returns +self+. The order of the combinations is indeterminate.
*
* When a block and a positive Integer argument +n+ are given, calls the block with each
* +n+-tuple repeated combination of the elements of +self+.
* The number of combinations is <tt>(n+1)(n+2)/2</tt>.
* If a positive integer argument +size+ is given,
* calls the block with each +size+-tuple repeated combination of the elements of +self+.
* The number of combinations is <tt>(size+1)(size+2)/2</tt>.
*
* +n+ = 1:
* Examples:
*
* a = [0, 1, 2]
* a.repeated_combination(1) {|combination| p combination }
* - +size+ is 1:
*
* Output:
* c = []
* [0, 1, 2].repeated_combination(1) {|combination| c.push(combination) }
* c # => [[0], [1], [2]]
*
* [0]
* [1]
* [2]
* - +size+ is 2:
*
* +n+ = 2:
* c = []
* [0, 1, 2].repeated_combination(2) {|combination| c.push(combination) }
* c # => [[0, 0], [0, 1], [0, 2], [1, 1], [1, 2], [2, 2]]
*
* a.repeated_combination(2) {|combination| p combination }
* If +size+ is zero, calls the block once with an empty array.
*
* Output:
* If +size+ is negative, does not call the block:
*
* [0, 0]
* [0, 1]
* [0, 2]
* [1, 1]
* [1, 2]
* [2, 2]
* [0, 1, 2].repeated_combination(-1) {|combination| fail 'Cannot happen' }
*
* If +n+ is zero, calls the block once with an empty +Array+.
*
* If +n+ is negative, does not call the block:
*
* a.repeated_combination(-1) {|combination| fail 'Cannot happen' }
*
* Returns a new Enumerator if no block given:
*
* a = [0, 1, 2]
* a.repeated_combination(2) # => #<Enumerator: [0, 1, 2]:combination(2)>
*
* Using Enumerators, it's convenient to show the combinations and counts
* for some values of +n+:
*
* e = a.repeated_combination(0)
* e.size # => 1
* e.to_a # => [[]]
* e = a.repeated_combination(1)
* e.size # => 3
* e.to_a # => [[0], [1], [2]]
* e = a.repeated_combination(2)
* e.size # => 6
* e.to_a # => [[0, 0], [0, 1], [0, 2], [1, 1], [1, 2], [2, 2]]
* With no block given, returns a new Enumerator.
*
* Related: see {Methods for Combining}[rdoc-ref:Array@Methods+for+Combining].
*/
static VALUE