[ci skip] Rdoc enhancements for Array (#3063)
* Per @nobu review * Rdoc enhancements for Array * Responses to review
This commit is contained in:
Burdette Lamar
GitHub
parent
a3cd01524c
commit
24739c62e5
Notes:
git
2020-05-16 06:13:06 +09:00
Merged-By: drbrain <drbrain@segment7.net>
274
array.c
274
array.c
@ -935,21 +935,26 @@ rb_check_to_array(VALUE ary)
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/*
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* call-seq:
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* Array.try_convert(obj) -> array or nil
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* Array.try_convert(obj) -> new_array or nil
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*
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* Tries to convert +obj+ into an array, using the +to_ary+ method. Returns
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* the converted array or +nil+ if +obj+ cannot be converted.
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* This method can be used to check if an argument is an array.
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* Tries to convert +obj+ to an \Array.
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*
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* Array.try_convert([1]) #=> [1]
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* Array.try_convert("1") #=> nil
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* When +obj+ is an
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* {Array-convertible object}[doc/implicit_conversion_rdoc.html#label-Array-Convertible+Objects]
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* (implements +to_ary+),
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* returns the \Array object created by converting it:
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*
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* if tmp = Array.try_convert(arg)
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* # the argument is an array
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* elsif tmp = String.try_convert(arg)
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* # the argument is a string
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* end
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* class ToAryReturnsArray < Set
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* def to_ary
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* self.to_a
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* end
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* end
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* as = ToAryReturnsArray.new([:foo, :bar, :baz])
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* Array.try_convert(as) # => [:foo, :bar, :baz]
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*
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* Returns +nil+ if +obj+ is not \Array-convertible:
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*
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* Array.try_convert(:foo) # => nil
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*/
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static VALUE
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@ -960,58 +965,96 @@ rb_ary_s_try_convert(VALUE dummy, VALUE ary)
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/*
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* call-seq:
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* Array.new(size=0, default=nil)
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* Array.new(array)
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* Array.new(size) {|index| block }
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* Array.new -> new_empty_array
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* Array.new(array) -> new_array
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* Array.new(size) -> new_array
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* Array.new(size, default_value) -> new_array
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* Array.new(size) {|index| ... } -> new_array
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*
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* Returns a new array.
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* Returns a new \Array.
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*
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* In the first form, if no arguments are sent, the new array will be empty.
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* When a +size+ and an optional +default+ are sent, an array is created with
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* +size+ copies of +default+. Take notice that all elements will reference the
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* same object +default+.
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* Argument +array+, if given, must be an
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* {Array-convertible object}[doc/implicit_conversion_rdoc.html#label-Array-Convertible+Objects]
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* (implements +to_ary+).
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*
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* The second form creates a copy of the array passed as a parameter (the
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* array is generated by calling to_ary on the parameter).
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* Argument +size+, if given must be an
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* {Integer-convertible object}[doc/implicit_conversion_rdoc.html#label-Integer-Convertible+Objects]
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* (implements +to_int+).
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*
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* first_array = ["Matz", "Guido"]
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* Argument +default_value+ may be any object.
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*
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* second_array = Array.new(first_array) #=> ["Matz", "Guido"]
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* ---
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*
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* first_array.equal? second_array #=> false
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* With no block and no arguments, returns a new empty \Array object:
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*
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* In the last form, an array of the given size is created. Each element in
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* this array is created by passing the element's index to the given block
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* and storing the return value.
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* a = Array.new
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* a # => []
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*
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* Array.new(3) {|index| index ** 2}
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* # => [0, 1, 4]
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* With no block and a single argument +array+,
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* returns a new \Array formed from +array+:
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*
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* == Common gotchas
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* a = Array.new([:foo, 'bar', 2])
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* a.class # => Array
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* a # => [:foo, "bar", 2]
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*
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* When sending the second parameter, the same object will be used as the
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* value for all the array elements:
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* With no block and a single argument +size+,
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* returns a new \Array of the given size
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* whose elements are all +nil+:
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*
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* a = Array.new(2, Hash.new)
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* # => [{}, {}]
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* a = Array.new(0)
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* a # => []
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* a = Array.new(3)
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* a # => [nil, nil, nil]
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*
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* a[0]['cat'] = 'feline'
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* a # => [{"cat"=>"feline"}, {"cat"=>"feline"}]
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* With no block and arguments +size+ and +default_value+,
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* returns an \Array of the given size;
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* each element is that same +default_value+:
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*
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* a[1]['cat'] = 'Felix'
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* a # => [{"cat"=>"Felix"}, {"cat"=>"Felix"}]
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* a = Array.new(3, 'x')
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* a # => ['x', 'x', 'x']
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* a[1].equal?(a[0]) # => true # Identity check.
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* a[2].equal?(a[0]) # => true # Identity check.
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*
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* Since all the Array elements store the same hash, changes to one of them
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* will affect them all.
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* With a block and argument +size+,
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* returns an \Array of the given size;
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* the block is called with each successive integer +index+;
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* the element for that +index+ is the return value from the block:
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*
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* If multiple copies are what you want, you should use the block
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* version which uses the result of that block each time an element
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* of the array needs to be initialized:
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* a = Array.new(3) { |index| "Element #{index}" }
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* a # => ["Element 0", "Element 1", "Element 2"]
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*
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* a = Array.new(2) {Hash.new}
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* a[0]['cat'] = 'feline'
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* a # => [{"cat"=>"feline"}, {}]
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* With a block and no argument,
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* or a single argument +0+,
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* ignores the block and returns a new empty \Array:
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*
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* a = Array.new(0) { |n| fail 'Cannot happen' }
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* a # => []
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* a = Array.new { |n| fail 'Cannot happen' }
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* a # => []
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*
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* With a block and arguments +size+ and +default_value+,
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* gives a warning message
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* ('warning: block supersedes default value argument'),
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* and assigns elements from the block's return values:
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*
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* Array.new(4, :default) {} # => [nil, nil, nil, nil]
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*
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* ---
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*
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* Raises an exception if +size+ is a negative integer:
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*
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* # Raises ArgumentError (negative array size):
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* Array.new(-1)
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* # Raises ArgumentError (negative array size):
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* Array.new(-1, :default)
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* # Raises ArgumentError (negative array size):
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* Array.new(-1) { |n| }
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*
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* Raises an exception if the single argument is neither \Array-convertible
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* nor \Integer-convertible.
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*
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* # Raises TypeError (no implicit conversion of Symbol into Integer):
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* Array.new(:foo)
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*/
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static VALUE
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@ -1193,18 +1236,20 @@ ary_take_first_or_last(int argc, const VALUE *argv, VALUE ary, enum ary_take_pos
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/*
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* call-seq:
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* ary << obj -> ary
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* ary << obj -> self
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*
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* Append---Pushes the given object on to the end of this array. This
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* expression returns the array itself, so several appends
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* may be chained together.
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* Appends +obj+ to +ary+; returns +self+:
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*
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* a = [ 1, 2 ]
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* a << "c" << "d" << [ 3, 4 ]
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* #=> [ 1, 2, "c", "d", [ 3, 4 ] ]
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* a
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* #=> [ 1, 2, "c", "d", [ 3, 4 ] ]
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* a = [:foo, 'bar', 2]
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* a1 = a << :baz
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* a1 # => [:foo, "bar", 2, :baz]
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* a1.equal?(a) # => true
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*
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* Appends +obj+ as one element, even if it is another \Array:
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*
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* a = [:foo, 'bar', 2]
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* a1 = a << [3, 4] # =>
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* a1 # => [:foo, "bar", 2, [3, 4]]
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*/
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VALUE
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@ -1232,19 +1277,21 @@ rb_ary_cat(VALUE ary, const VALUE *argv, long len)
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/*
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* call-seq:
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* ary.push(obj, ...) -> ary
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* ary.append(obj, ...) -> ary
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* ary.push(*objects) -> self
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* ary.append(*objects) -> self
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*
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* Append --- Pushes the given object(s) on to the end of this array. This
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* expression returns the array itself, so several appends
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* may be chained together. See also Array#pop for the opposite
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* effect.
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* Appends each argument in +objects+ to the array; returns +self+:
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*
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* a = [ "a", "b", "c" ]
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* a.push("d", "e", "f")
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* #=> ["a", "b", "c", "d", "e", "f"]
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* [1, 2, 3].push(4).push(5)
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* #=> [1, 2, 3, 4, 5]
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* a = [:foo, 'bar', 2]
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* a1 = a.push(:baz, :bat)
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* a1 # => [:foo, "bar", 2, :baz, :bat]
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* a1.equal?(a) # => true
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*
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* Appends each argument as one element, even if it is another \Array:
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*
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* a = [:foo, 'bar', 2]
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* a1 = a.push([:baz, :bat], [:bam, :bad])
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* a1 # => [:foo, "bar", 2, [:baz, :bat], [:bam, :bad]]
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*/
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static VALUE
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@ -1274,20 +1321,62 @@ rb_ary_pop(VALUE ary)
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/*
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* call-seq:
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* ary.pop -> obj or nil
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* ary.pop(n) -> new_ary
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* ary.pop -> obj or nil
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* ary.pop(n) -> new_array
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*
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* Removes the last element from +self+ and returns it, or
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* +nil+ if the array is empty.
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* Removes and returns trailing elements from the array.
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*
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* If a number +n+ is given, returns an array of the last +n+ elements
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* (or less) just like <code>array.slice!(-n, n)</code> does. See also
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* Array#push for the opposite effect.
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* Argument +n+, if given, must be an
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* {Integer-convertible object}[doc/implicit_conversion_rdoc.html#label-Integer-Convertible+Objects]
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* (implements +to_int+).
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*
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* a = [ "a", "b", "c", "d" ]
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* a.pop #=> "d"
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* a.pop(2) #=> ["b", "c"]
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* a #=> ["a"]
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* ---
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*
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* When no argument is given and the array is not empty,
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* removes and returns the last element in the array:
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*
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* a = [:foo, 'bar', 2]
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* a.pop # => 2
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* a # => [:foo, "bar"]
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*
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* Returns +nil+ if the array is empty:
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*
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* a = []
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* a.pop # => nil
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*
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* ---
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*
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* When argument +n+ is given and is non-negative and in range,
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* removes and returns the last +n+ elements in a new \Array:
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*
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* a = [:foo, 'bar', 2]
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* a1 = a.pop(2)
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* a1 # => ["bar", 2]
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* a # => [:foo]
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* a.pop(0) # => []
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*
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* If +n+ is positive and out of range,
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* removes and returns all elements:
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*
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* a = [:foo, 'bar', 2]
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* a1 = a.pop(50)
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* a1 # => [:foo, "bar", 2]
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* a # => []
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* a.pop(1) # => []
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*
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* ---
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*
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* Raises an exception if +n+ is negative:
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*
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* a = [:foo, 'bar', 2]
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* # Raises ArgumentError (negative array size):
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* a1 = a.pop(-1)
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*
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* Raises an exception if +n+ is not \Integer-convertible (implements +to_int+).
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*
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* a = [:foo, 'bar', 2]
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* # Raises TypeError (no implicit conversion of String into Integer):
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* a1 = a.pop('x')
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*/
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static VALUE
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@ -6621,12 +6710,32 @@ rb_ary_deconstruct(VALUE ary)
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}
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/*
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* Arrays are ordered, integer-indexed collections of any object.
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* An \Array is an ordered, integer-indexed collection of objects,
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* called _elements_. Any object may be an \Array element.
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*
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* Array indexing starts at 0, as in C or Java. A negative index is assumed
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* to be relative to the end of the array---that is, an index of -1 indicates
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* the last element of the array, -2 is the next to last element in the
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* array, and so on.
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* == \Array Indexes
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*
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* \Array indexing starts at 0, as in C or Java.
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*
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* A positive index is an offset from the first element:
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* - Index 0 indicates the first element.
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* - Index 1 indicates the second element.
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* - ...
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*
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* A negative index is an offset, backwards, from the end of the array:
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* - Index -1 indicates the last element.
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* - Index -2 indicates the next-to-last element.
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* - ...
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*
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* A non-negative index is <i>in range</i> if it is smaller than
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* the size of the array. For a 3-element array:
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* - Indexes 0 through 2 are in range.
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* - Index 3 is out of range.
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*
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* A negative index is <i>in range</i> if its absolute value is
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* not larger than the size of the array. For a 3-element array:
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* - Indexes -1 through -3 are in range.
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* - Index -4 is out of range.
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*
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* == Creating Arrays
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*
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@ -6855,7 +6964,6 @@ rb_ary_deconstruct(VALUE ary)
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* arr = [1, 2, 3, 4, 5, 6]
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* arr.keep_if {|a| a < 4} #=> [1, 2, 3]
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* arr #=> [1, 2, 3]
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*
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*/
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void
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@ -30,7 +30,41 @@ NoMethodError.
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You may also use <code>::</code> to designate a receiver, but this is rarely
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used due to the potential for confusion with <code>::</code> for namespaces.
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=== Safe navigation operator
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=== Chaining \Method Calls
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You can "chain" method calls by immediately following one method call with another.
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This example chains methods Array#append and Array#compact:
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a = [:foo, 'bar', 2]
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a1 = [:baz, nil, :bam, nil]
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a2 = a.append(*a1).compact
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a2 # => [:foo, "bar", 2, :baz, :bam]
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Details:
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- First method <tt>merge</tt> creates a copy of <tt>a</tt>,
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appends (separately) each element of <tt>a1</tt> to the copy, and returns
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[:foo, "bar", 2, :baz, nil, :bam, nil]
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- Chained method <tt>compact</tt> creates a copy of that return value,
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removes its <tt>nil</tt>-valued entries, and returns
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[:foo, "bar", 2, :baz, :bam]
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You can chain methods that are in different classes.
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This example chains methods Hash#to_a and Array#reverse:
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h = {foo: 0, bar: 1, baz: 2}
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h.to_a.reverse # => [[:baz, 2], [:bar, 1], [:foo, 0]]
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Details:
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- First method Hash#to_a converts <tt>a</tt> to an \Array, and returns
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[[:foo, 0], [:bar, 1], [:baz, 2]]
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- Chained method Array#reverse creates copy of that return value,
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reverses it, and returns
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[[:baz, 2], [:bar, 1], [:foo, 0]]
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=== Safe Navigation Operator
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<code>&.</code>, called "safe navigation operator", allows to skip method call
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when receiver is +nil+. It returns +nil+ and doesn't evaluate method's arguments
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