Class: Array

Inherits:
Object show all
Includes:
Enumerable
Defined in:
array.c

Overview

Arrays are ordered, integer-indexed collections of any object. Array indexing starts at 0, as in C or Java. A negative index is assumed to be relative to the end of the array—that is, an index of -1 indicates the last element of the array, -2 is the next to last element in the array, and so on.

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Enumerable

#all?, #any?, #detect, #each_with_index, #entries, #find, #find_all, #grep, #inject, #max, #member?, #min, #partition, #sort_by

Constructor Details

#new(size = 0, obj = nil) ⇒ Object #new(array) ⇒ Object #new(size) {|index| ... } ⇒ Object

Returns a new array. In the first form, the new array is empty. In the second it is created with size copies of obj (that is, size references to the same obj). The third form creates a copy of the array passed as a parameter (the array is generated by calling to_ary on the parameter). In the last form, an array of the given size is created. Each element in this array is calculated by passing the element’s index to the given block and storing the return value.

Array.new
Array.new(2)
Array.new(5, "A")

# only one copy of the object is created
a = Array.new(2, Hash.new)
a[0]['cat'] = 'feline'
a
a[1]['cat'] = 'Felix'
a

# here multiple copies are created
a = Array.new(2) { Hash.new }
a[0]['cat'] = 'feline'
a

squares = Array.new(5) {|i| i*i}
squares

copy = Array.new(squares)

Overloads:



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# File 'array.c', line 266

static VALUE
rb_ary_initialize(argc, argv, ary)
int argc;

Class Method Details

.[] ⇒ Object

Returns a new array populated with the given objects.

Array.[]( 1, 'a', /^A/ )
Array[ 1, 'a', /^A/ ]
[ 1, 'a', /^A/ ]



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# File 'array.c', line 331

static VALUE
rb_ary_s_create(argc, argv, klass)
int argc;

Instance Method Details

#&(other_array) ⇒ Object

Set Intersection—Returns a new array containing elements common to the two arrays, with no duplicates.

[ 1, 1, 3, 5 ] & [ 1, 2, 3 ]   #=> [ 1, 3 ]



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# File 'array.c', line 2676

static VALUE
rb_ary_and(ary1, ary2)
VALUE ary1, ary2;

#*(int) ⇒ Array #*(str) ⇒ String

Repetition—With a String argument, equivalent to self.join(str). Otherwise, returns a new array built by concatenating the int copies of self.

[ 1, 2, 3 ] * 3    #=> [ 1, 2, 3, 1, 2, 3, 1, 2, 3 ]
[ 1, 2, 3 ] * ","  #=> "1,2,3"

Overloads:



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# File 'array.c', line 2361

static VALUE
rb_ary_times(ary, times)
VALUE ary, times;

#+(other_array) ⇒ Array

Concatenation—Returns a new array built by concatenating the two arrays together to produce a third array.

[ 1, 2, 3 ] + [ 4, 5 ]    #=> [ 1, 2, 3, 4, 5 ]

Returns:



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# File 'array.c', line 2308

VALUE
rb_ary_plus(x, y)
VALUE x, y;

#-(other_array) ⇒ Array

Array Difference—Returns a new array that is a copy of the original array, removing any items that also appear in other_array. (If you need set-like behavior, see the library class Set.)

[ 1, 1, 2, 2, 3, 3, 4, 5 ] - [ 1, 2, 4 ]  #=>  [ 3, 3, 5 ]

Returns:



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# File 'array.c', line 2647

static VALUE
rb_ary_diff(ary1, ary2)
VALUE ary1, ary2;

#<<(obj) ⇒ Array

Append—Pushes the given object on to the end of this array. This expression returns the array itself, so several appends may be chained together.

[ 1, 2 ] << "c" << "d" << [ 3, 4 ]
        #=>  [ 1, 2, "c", "d", [ 3, 4 ] ]

Returns:



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# File 'array.c', line 400

VALUE
rb_ary_push(ary, item)
VALUE ary;

#<=>(other_array) ⇒ -1, ...

Comparison—Returns an integer (-1, 0, or +1) if this array is less than, equal to, or greater than other_array. Each object in each array is compared (using <=>). If any value isn’t equal, then that inequality is the return value. If all the values found are equal, then the return is based on a comparison of the array lengths. Thus, two arrays are “equal” according to Array#<=> if and only if they have the same length and the value of each element is equal to the value of the corresponding element in the other array.

[ "a", "a", "c" ]    <=> [ "a", "b", "c" ]   #=> -1
[ 1, 2, 3, 4, 5, 6 ] <=> [ 1, 2 ]            #=> +1

Returns:

  • (-1, 0, +1) 


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# File 'array.c', line 2594

VALUE
rb_ary_cmp(ary1, ary2)
VALUE ary1, ary2;

#==(other_array) ⇒ Boolean

Equality—Two arrays are equal if they contain the same number of elements and if each element is equal to (according to Object.==) the corresponding element in the other array.

[ "a", "c" ]    == [ "a", "c", 7 ]     #=> false
[ "a", "c", 7 ] == [ "a", "c", 7 ]     #=> true
[ "a", "c", 7 ] == [ "a", "d", "f" ]   #=> false

Returns:

  • (Boolean) 


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# File 'array.c', line 2476

static VALUE
rb_ary_equal(ary1, ary2)
VALUE ary1, ary2;

#[](index) ⇒ Object? #[](start, length) ⇒ Array? #[](range) ⇒ Array? #slice(index) ⇒ Object? #slice(start, length) ⇒ Array? #slice(range) ⇒ Array?

Element Reference—Returns the element at index, or returns a subarray starting at start and continuing for length elements, or returns a subarray specified by range. Negative indices count backward from the end of the array (-1 is the last element). Returns nil if the index (or starting index) are out of range.

a = [ "a", "b", "c", "d", "e" ]
a[2] +  a[0] + a[1]    #=> "cab"
a[6]                   #=> nil
a[1, 2]                #=> [ "b", "c" ]
a[1..3]                #=> [ "b", "c", "d" ]
a[4..7]                #=> [ "e" ]
a[6..10]               #=> nil
a[-3, 3]               #=> [ "c", "d", "e" ]
# special cases
a[5]                   #=> nil
a[5, 1]                #=> []
a[5..10]               #=> []

Overloads:



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# File 'array.c', line 660

VALUE
rb_ary_aref(argc, argv, ary)
int argc;

#[]=(index) ⇒ Object #[]=(start, length) ⇒ Object, ... #[]=(range) ⇒ Object, ...

Element Assignment—Sets the element at index, or replaces a subarray starting at start and continuing for length elements, or replaces a subarray specified by range. If indices are greater than the current capacity of the array, the array grows automatically. A negative indices will count backward from the end of the array. Inserts elements if length is zero. If nil is used in the second and third form, deletes elements from self. An IndexError is raised if a negative index points past the beginning of the array. See also Array#push, and Array#unshift.

a = Array.new
a[4] = "4";                 #=> [nil, nil, nil, nil, "4"]
a[0, 3] = [ 'a', 'b', 'c' ] #=> ["a", "b", "c", nil, "4"]
a[1..2] = [ 1, 2 ]          #=> ["a", 1, 2, nil, "4"]
a[0, 2] = "?"               #=> ["?", 2, nil, "4"]
a[0..2] = "A"               #=> ["A", "4"]
a[-1]   = "Z"               #=> ["A", "Z"]
a[1..-1] = nil              #=> ["A"]

Overloads:



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# File 'array.c', line 1041

static VALUE
rb_ary_aset(argc, argv, ary)
int argc;

#assoc(obj) ⇒ Array?

Searches through an array whose elements are also arrays comparing obj with the first element of each contained array using obj.==. Returns the first contained array that matches (that is, the first associated array), or nil if no match is found. See also Array#rassoc.

s1 = [ "colors", "red", "blue", "green" ]
s2 = [ "letters", "a", "b", "c" ]
s3 = "foo"
a  = [ s1, s2, s3 ]
a.assoc("letters")  #=> [ "letters", "a", "b", "c" ]
a.assoc("foo")      #=> nil

Returns:



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# File 'array.c', line 2414

VALUE
rb_ary_assoc(ary, key)
VALUE ary, key;

#at(index) ⇒ Object?

Returns the element at index. A negative index counts from the end of self. Returns nil if the index is out of range. See also Array#[]. (Array#at is slightly faster than Array#[], as it does not accept ranges and so on.)

a = [ "a", "b", "c", "d", "e" ]
a.at(0)     #=> "a"
a.at(-1)    #=> "e"

Returns:



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# File 'array.c', line 718

static VALUE
rb_ary_at(ary, pos)
VALUE ary, pos;

#clear ⇒ Array

Removes all elements from self.

a = [ "a", "b", "c", "d", "e" ]
a.clear    #=> [ ]

Returns:



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# File 'array.c', line 2192

VALUE
rb_ary_clear(ary)
VALUE ary;

#collect {|item| ... } ⇒ Array #map {|item| ... } ⇒ Array

Invokes block once for each element of self. Creates a new array containing the values returned by the block. See also Enumerable#collect.

a = [ "a", "b", "c", "d" ]
a.collect {|x| x + "!" }   #=> ["a!", "b!", "c!", "d!"]
a                          #=> ["a", "b", "c", "d"]

Overloads:

  • #collect {|item| ... } ⇒ Array

    Yields:

    • (item)

    Returns:

  • #map {|item| ... } ⇒ Array

    Yields:

    • (item)

    Returns:



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# File 'array.c', line 1699

static VALUE
rb_ary_collect(ary)
VALUE ary;

#collect! {|item| ... } ⇒ Array #map! {|item| ... } ⇒ Array

Invokes the block once for each element of self, replacing the element with the value returned by block. See also Enumerable#collect.

a = [ "a", "b", "c", "d" ]
a.collect! {|x| x + "!" }
a             #=>  [ "a!", "b!", "c!", "d!" ]

Overloads:

  • #collect! {|item| ... } ⇒ Array

    Yields:

    • (item)

    Returns:

  • #map! {|item| ... } ⇒ Array

    Yields:

    • (item)

    Returns:



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# File 'array.c', line 1731

static VALUE
rb_ary_collect_bang(ary)
VALUE ary;

#compact ⇒ Array

Returns a copy of self with all nil elements removed.

[ "a", nil, "b", nil, "c", nil ].compact
                  #=> [ "a", "b", "c" ]

Returns:



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# File 'array.c', line 2836

static VALUE
rb_ary_compact(ary)
VALUE ary;

#compact! ⇒ Array?

Removes nil elements from array. Returns nil if no changes were made.

[ "a", nil, "b", nil, "c" ].compact! #=> [ "a", "b", "c" ]
[ "a", "b", "c" ].compact!           #=> nil

Returns:



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# File 'array.c', line 2803

static VALUE
rb_ary_compact_bang(ary)
VALUE ary;

#concat(other_array) ⇒ Array

Appends the elements in other_array to self.

[ "a", "b" ].concat( ["c", "d"] ) #=> [ "a", "b", "c", "d" ]

Returns:



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# File 'array.c', line 2334

VALUE
rb_ary_concat(x, y)
VALUE x, y;

#delete(obj) ⇒ Object? #delete(obj) { ... } ⇒ Object?

Deletes items from self that are equal to obj. If the item is not found, returns nil. If the optional code block is given, returns the result of block if the item is not found.

a = [ "a", "b", "b", "b", "c" ]
a.delete("b")                   #=> "b"
a                               #=> ["a", "c"]
a.delete("z")                   #=> nil
a.delete("z") { "not found" }   #=> "not found"

Overloads:



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# File 'array.c', line 1847

VALUE
rb_ary_delete(ary, item)
VALUE ary;

#delete_at(index) ⇒ Object?

Deletes the element at the specified index, returning that element, or nil if the index is out of range. See also Array#slice!.

a = %w( ant bat cat dog )
a.delete_at(2)    #=> "cat"
a                 #=> ["ant", "bat", "dog"]
a.delete_at(99)   #=> nil

Returns:



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# File 'array.c', line 1921

static VALUE
rb_ary_delete_at_m(ary, pos)
VALUE ary, pos;

#delete_if {|item| ... } ⇒ Array

Deletes every element of self for which block evaluates to true.

a = [ "a", "b", "c" ]
a.delete_if {|x| x >= "b" }   #=> ["a"]

Yields:

  • (item)

Returns:



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# File 'array.c', line 2041

static VALUE
rb_ary_delete_if(ary)
VALUE ary;

#each {|item| ... } ⇒ Array

Calls block once for each element in self, passing that element as a parameter.

a = [ "a", "b", "c" ]
a.each {|x| print x, " -- " }

produces:

a -- b -- c --

Yields:

  • (item)

Returns:



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# File 'array.c', line 1131

VALUE
rb_ary_each(ary)
VALUE ary;

#each_index {|index| ... } ⇒ Array

Same as Array#each, but passes the index of the element instead of the element itself.

a = [ "a", "b", "c" ]
a.each_index {|x| print x, " -- " }

produces:

0 -- 1 -- 2 --

Yields:

Returns:



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# File 'array.c', line 1158

static VALUE
rb_ary_each_index(ary)
VALUE ary;

#empty? ⇒ Boolean

Returns true if self array contains no elements.

[].empty?   #=> true

Returns:

  • (Boolean) 


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# File 'array.c', line 1225

static VALUE
rb_ary_empty_p(ary)
VALUE ary;

#eql?(other) ⇒ Boolean

Returns true if array and other are the same object, or are both arrays with the same content.

Returns:

  • (Boolean) 


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# File 'array.c', line 2505

static VALUE
rb_ary_eql(ary1, ary2)
VALUE ary1, ary2;

#fetch(index) ⇒ Object #fetch(index, default) ⇒ Object #fetch(index) {|index| ... } ⇒ Object

Tries to return the element at position index. If the index lies outside the array, the first form throws an IndexError exception, the second form returns default, and the third form returns the value of invoking the block, passing in the index. Negative values of index count from the end of the array.

a = [ 11, 22, 33, 44 ]
a.fetch(1)               #=> 22
a.fetch(-1)              #=> 44
a.fetch(4, 'cat')        #=> "cat"
a.fetch(4) { |i| i*i }   #=> 16

Overloads:



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# File 'array.c', line 821

static VALUE
rb_ary_fetch(argc, argv, ary)
int argc;

#fill(obj) ⇒ Array #fill(obj, start[, length]) ⇒ Array #fill(obj, range) ⇒ Array #fill {|index| ... } ⇒ Array #fill(start[, length]) {|index| ... } ⇒ Array #fill(range) {|index| ... } ⇒ Array

The first three forms set the selected elements of self (which may be the entire array) to obj. A start of nil is equivalent to zero. A length of nil is equivalent to self.length. The last three forms fill the array with the value of the block. The block is passed the absolute index of each element to be filled.

a = [ "a", "b", "c", "d" ]
a.fill("x")              #=> ["x", "x", "x", "x"]
a.fill("z", 2, 2)        #=> ["x", "x", "z", "z"]
a.fill("y", 0..1)        #=> ["y", "y", "z", "z"]
a.fill {|i| i*i}         #=> [0, 1, 4, 9]
a.fill(-2) {|i| i*i*i}   #=> [0, 1, 8, 27]

Overloads:



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# File 'array.c', line 2229

static VALUE
rb_ary_fill(argc, argv, ary)
int argc;

#first ⇒ Object? #first(n) ⇒ Array

Returns the first element, or the first n elements, of the array. If the array is empty, the first form returns nil, and the second form returns an empty array.

a = [ "q", "r", "s", "t" ]
a.first    #=> "q"
a.first(1) #=> ["q"]
a.first(3) #=> ["q", "r", "s"]

Overloads:



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# File 'array.c', line 740

static VALUE
rb_ary_first(argc, argv, ary)
int argc;

#flatten ⇒ Array

Returns a new array that is a one-dimensional flattening of this array (recursively). That is, for every element that is an array, extract its elements into the new array.

s = [ 1, 2, 3 ]           #=> [1, 2, 3]
t = [ 4, 5, 6, [7, 8] ]   #=> [4, 5, 6, [7, 8]]
a = [ s, t, 9, 10 ]       #=> [[1, 2, 3], [4, 5, 6, [7, 8]], 9, 10]
a.flatten                 #=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10

Returns:



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# File 'array.c', line 2957

static VALUE
rb_ary_flatten(ary)
VALUE ary;

#flatten! ⇒ Array?

Flattens self in place. Returns nil if no modifications were made (i.e., array contains no subarrays.)

a = [ 1, 2, [3, [4, 5] ] ]
a.flatten!   #=> [1, 2, 3, 4, 5]
a.flatten!   #=> nil
a            #=> [1, 2, 3, 4, 5]

Returns:



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# File 'array.c', line 2917

static VALUE
rb_ary_flatten_bang(ary)
VALUE ary;

#frozen? ⇒ Boolean

Return true if this array is frozen (or temporarily frozen while being sorted).

Returns:

  • (Boolean) 


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# File 'array.c', line 89

static VALUE
rb_ary_frozen_p(ary)
VALUE ary;

#hash ⇒ Fixnum

Compute a hash-code for this array. Two arrays with the same content will have the same hash code (and will compare using eql?).

Returns:



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# File 'array.c', line 2529

static VALUE
rb_ary_hash(ary)
VALUE ary;

#include?(obj) ⇒ Boolean

Returns true if the given object is present in self (that is, if any object == anObject), false otherwise.

a = [ "a", "b", "c" ]
a.include?("b")   #=> true
a.include?("z")   #=> false

Returns:

  • (Boolean) 


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# File 'array.c', line 2558

VALUE
rb_ary_includes(ary, item)
VALUE ary;

#index(obj) ⇒ Integer?

Returns the index of the first object in self such that is == to obj. Returns nil if no match is found.

a = [ "a", "b", "c" ]
a.index("b")   #=> 1
a.index("z")   #=> nil

Returns:



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# File 'array.c', line 864

static VALUE
rb_ary_index(ary, val)
VALUE ary;

#indexes(i1, i2, ...iN) ⇒ Array #indices(i1, i2, ...iN) ⇒ Array

Deprecated; use Array#values_at.

Overloads:

  • #indexes(i1, i2, ...iN) ⇒ Array

    Returns:

  • #indices(i1, i2, ...iN) ⇒ Array

    Returns:



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# File 'array.c', line 917

static VALUE
rb_ary_indexes(argc, argv, ary)
int argc;

#indexes(i1, i2, ...iN) ⇒ Array #indices(i1, i2, ...iN) ⇒ Array

Deprecated; use Array#values_at.

Overloads:

  • #indexes(i1, i2, ...iN) ⇒ Array

    Returns:

  • #indices(i1, i2, ...iN) ⇒ Array

    Returns:



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# File 'array.c', line 917

static VALUE
rb_ary_indexes(argc, argv, ary)
int argc;

#replace(other_array) ⇒ Array

Replaces the contents of self with the contents of other_array, truncating or expanding if necessary.

a = [ "a", "b", "c", "d", "e" ]
a.replace([ "x", "y", "z" ])   #=> ["x", "y", "z"]
a                              #=> ["x", "y", "z"]

Returns:



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# File 'array.c', line 2162

static VALUE
rb_ary_replace(copy, orig)
VALUE copy, orig;

#insert(index, obj...) ⇒ Array

Inserts the given values before the element with the given index (which may be negative).

a = %w{ a b c d }
a.insert(2, 99)         #=> ["a", "b", 99, "c", "d"]
a.insert(-2, 1, 2, 3)   #=> ["a", "b", 99, "c", 1, 2, 3, "d"]

Returns:



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# File 'array.c', line 1093

static VALUE
rb_ary_insert(argc, argv, ary)
int argc;

#inspect ⇒ String

Create a printable version of array.

Returns:



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# File 'array.c', line 1459

static VALUE
rb_ary_inspect(ary)
VALUE ary;

#join(sep = $,) ⇒ String

Returns a string created by converting each element of the array to a string, separated by sep.

[ "a", "b", "c" ].join        #=> "abc"
[ "a", "b", "c" ].join("-")   #=> "a-b-c"

Returns:



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# File 'array.c', line 1317

static VALUE
rb_ary_join_m(argc, argv, ary)
int argc;

#last ⇒ Object? #last(n) ⇒ Array

Returns the last element(s) of self. If the array is empty, the first form returns nil.

[ "w", "x", "y", "z" ].last   #=> "z"

Overloads:



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# File 'array.c', line 776

static VALUE
rb_ary_last(argc, argv, ary)
int argc;

#length ⇒ Integer Also known as: size

Returns the number of elements in self. May be zero.

[ 1, 2, 3, 4, 5 ].length   #=> 5

Returns:



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# File 'array.c', line 1209

static VALUE
rb_ary_length(ary)
VALUE ary;

#collect {|item| ... } ⇒ Array #map {|item| ... } ⇒ Array

Invokes block once for each element of self. Creates a new array containing the values returned by the block. See also Enumerable#collect.

a = [ "a", "b", "c", "d" ]
a.collect {|x| x + "!" }   #=> ["a!", "b!", "c!", "d!"]
a                          #=> ["a", "b", "c", "d"]

Overloads:

  • #collect {|item| ... } ⇒ Array

    Yields:

    • (item)

    Returns:

  • #map {|item| ... } ⇒ Array

    Yields:

    • (item)

    Returns:



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# File 'array.c', line 1699

static VALUE
rb_ary_collect(ary)
VALUE ary;

#collect! {|item| ... } ⇒ Array #map! {|item| ... } ⇒ Array

Invokes the block once for each element of self, replacing the element with the value returned by block. See also Enumerable#collect.

a = [ "a", "b", "c", "d" ]
a.collect! {|x| x + "!" }
a             #=>  [ "a!", "b!", "c!", "d!" ]

Overloads:

  • #collect! {|item| ... } ⇒ Array

    Yields:

    • (item)

    Returns:

  • #map! {|item| ... } ⇒ Array

    Yields:

    • (item)

    Returns:



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# File 'array.c', line 1731

static VALUE
rb_ary_collect_bang(ary)
VALUE ary;

#nitems ⇒ Integer

Returns the number of non-nil elements in self. May be zero.

[ 1, nil, 3, nil, 5 ].nitems   #=> 3

Returns:



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# File 'array.c', line 2855

static VALUE
rb_ary_nitems(ary)
VALUE ary;

#pack ⇒ Object

Packs the contents of arr into a binary sequence according to the directives in aTemplateString (see the table below) Directives “A,” “a,” and “Z” may be followed by a count, which gives the width of the resulting field. The remaining directives also may take a count, indicating the number of array elements to convert. If the count is an asterisk (“*”), all remaining array elements will be converted. Any of the directives “sSiIlL” may be followed by an underscore (“_”) to use the underlying platform’s native size for the specified type; otherwise, they use a platform-independent size. Spaces are ignored in the template string. See also String#unpack.

a = [ "a", "b", "c" ]
n = [ 65, 66, 67 ]
a.pack("A3A3A3")   #=> "a  b  c  "
a.pack("a3a3a3")   #=> "a\000\000b\000\000c\000\000"
n.pack("ccc")      #=> "ABC"

Directives for pack.

Directive    Meaning
---------------------------------------------------------------
    @     |  Moves to absolute position
    A     |  ASCII string (space padded, count is width)
    a     |  ASCII string (null padded, count is width)
    B     |  Bit string (descending bit order)
    b     |  Bit string (ascending bit order)
    C     |  Unsigned char
    c     |  Char
    D, d  |  Double-precision float, native format
    E     |  Double-precision float, little-endian byte order
    e     |  Single-precision float, little-endian byte order
    F, f  |  Single-precision float, native format
    G     |  Double-precision float, network (big-endian) byte order
    g     |  Single-precision float, network (big-endian) byte order
    H     |  Hex string (high nibble first)
    h     |  Hex string (low nibble first)
    I     |  Unsigned integer
    i     |  Integer
    L     |  Unsigned long
    l     |  Long
    M     |  Quoted printable, MIME encoding (see RFC2045)
    m     |  Base64 encoded string
    N     |  Long, network (big-endian) byte order
    n     |  Short, network (big-endian) byte-order
    P     |  Pointer to a structure (fixed-length string)
    p     |  Pointer to a null-terminated string
    Q, q  |  64-bit number
    S     |  Unsigned short
    s     |  Short
    U     |  UTF-8
    u     |  UU-encoded string
    V     |  Long, little-endian byte order
    v     |  Short, little-endian byte order
    w     |  BER-compressed integer\fnm
    X     |  Back up a byte
    x     |  Null byte
    Z     |  Same as ``a'', except that null is added with *



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# File 'pack.c', line 440

static VALUE
pack_pack(ary, fmt)
VALUE ary, fmt;

#pop ⇒ Object?

Removes the last element from self and returns it, or nil if the array is empty.

a = [ "a", "m", "z" ]
a.pop   #=> "z"
a       #=> ["a", "m"]

Returns:



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# File 'array.c', line 446

VALUE
rb_ary_pop(ary)
VALUE ary;

#push(obj, ...) ⇒ Array

Append—Pushes the given object(s) on to the end of this array. This expression returns the array itself, so several appends may be chained together.

a = [ "a", "b", "c" ]
a.push("d", "e", "f")
        #=> ["a", "b", "c", "d", "e", "f"]

Returns:



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# File 'array.c', line 422

static VALUE
rb_ary_push_m(argc, argv, ary)
int argc;

#rassoc(key) ⇒ Array?

Searches through the array whose elements are also arrays. Compares key with the second element of each contained array using ==. Returns the first contained array that matches. See also Array#assoc.

a = [ [ 1, "one"], [2, "two"], [3, "three"], ["ii", "two"] ]
a.rassoc("two")    #=> [2, "two"]
a.rassoc("four")   #=> nil

Returns:



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# File 'array.c', line 2445

VALUE
rb_ary_rassoc(ary, value)
VALUE ary, value;

#reject {|item| ... } ⇒ Array

Returns a new array containing the items in self for which the block is not true.

Yields:

  • (item)

Returns:



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# File 'array.c', line 2021

static VALUE
rb_ary_reject(ary)
VALUE ary;

#reject! {|item| ... } ⇒ Array?

Equivalent to Array#delete_if, deleting elements from self for which the block evaluates to true, but returns nil if no changes were made. Also see Enumerable#reject.

Yields:

  • (item)

Returns:



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# File 'array.c', line 1991

static VALUE
rb_ary_reject_bang(ary)
VALUE ary;

#replace(other_array) ⇒ Array

Replaces the contents of self with the contents of other_array, truncating or expanding if necessary.

a = [ "a", "b", "c", "d", "e" ]
a.replace([ "x", "y", "z" ])   #=> ["x", "y", "z"]
a                              #=> ["x", "y", "z"]

Returns:



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# File 'array.c', line 2162

static VALUE
rb_ary_replace(copy, orig)
VALUE copy, orig;

#reverse ⇒ Array

Returns a new array containing self’s elements in reverse order.

[ "a", "b", "c" ].reverse   #=> ["c", "b", "a"]
[ 1 ].reverse               #=> [1]

Returns:



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# File 'array.c', line 1551

static VALUE
rb_ary_reverse_m(ary)
VALUE ary;

#reverse! ⇒ Array

Reverses self in place.

a = [ "a", "b", "c" ]
a.reverse!       #=> ["c", "b", "a"]
a                #=> ["c", "b", "a"]

Returns:



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# File 'array.c', line 1534

static VALUE
rb_ary_reverse_bang(ary)
VALUE ary;

#reverse_each {|item| ... } ⇒ Object

Same as Array#each, but traverses self in reverse order.

a = [ "a", "b", "c" ]
a.reverse_each {|x| print x, " " }

produces:

c b a

Yields:

  • (item) 


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# File 'array.c', line 1185

static VALUE
rb_ary_reverse_each(ary)
VALUE ary;

#rindex(obj) ⇒ Integer?

Returns the index of the last object in array == to obj. Returns nil if no match is found.

a = [ "a", "b", "b", "b", "c" ]
a.rindex("b")   #=> 3
a.rindex("z")   #=> nil

Returns:



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# File 'array.c', line 891

static VALUE
rb_ary_rindex(ary, val)
VALUE ary;

#select {|item| ... } ⇒ Array

Invokes the block passing in successive elements from array, returning an array containing those elements for which the block returns a true value (equivalent to Enumerable#select).

a = %w{ a b c d e f }
a.select {|v| v =~ /[aeiou]/}   #=> ["a", "e"]

Yields:

  • (item)

Returns:



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# File 'array.c', line 1814

static VALUE
rb_ary_select(ary)
VALUE ary;

#shift ⇒ Object?

Returns the first element of self and removes it (shifting all other elements down by one). Returns nil if the array is empty.

args = [ "-m", "-q", "filename" ]
args.shift   #=> "-m"
args         #=> ["-q", "filename"]

Returns:



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# File 'array.c', line 495

VALUE
rb_ary_shift(ary)
VALUE ary;

#[](index) ⇒ Object? #[](start, length) ⇒ Array? #[](range) ⇒ Array? #slice(index) ⇒ Object? #slice(start, length) ⇒ Array? #slice(range) ⇒ Array?

Element Reference—Returns the element at index, or returns a subarray starting at start and continuing for length elements, or returns a subarray specified by range. Negative indices count backward from the end of the array (-1 is the last element). Returns nil if the index (or starting index) are out of range.

a = [ "a", "b", "c", "d", "e" ]
a[2] +  a[0] + a[1]    #=> "cab"
a[6]                   #=> nil
a[1, 2]                #=> [ "b", "c" ]
a[1..3]                #=> [ "b", "c", "d" ]
a[4..7]                #=> [ "e" ]
a[6..10]               #=> nil
a[-3, 3]               #=> [ "c", "d", "e" ]
# special cases
a[5]                   #=> nil
a[5, 1]                #=> []
a[5..10]               #=> []

Overloads:



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# File 'array.c', line 660

VALUE
rb_ary_aref(argc, argv, ary)
int argc;

#slice!(index) ⇒ Object? #slice!(start, length) ⇒ nil #slice!(range) ⇒ nil

Deletes the element(s) given by an index (optionally with a length) or by a range. Returns the deleted object, subarray, or nil if the index is out of range. Equivalent to:

def slice!(*args)
  result = self[*args]
  self[*args] = nil
  result
end

a = [ "a", "b", "c" ]
a.slice!(1)     #=> "b"
a               #=> ["a", "c"]
a.slice!(-1)    #=> "c"
a               #=> ["a"]
a.slice!(100)   #=> nil
a               #=> ["a"]

Overloads:

  • #slice!(index) ⇒ Object?

    Returns:

  • #slice!(start, length) ⇒ nil

    Returns:

    • (nil)
  • #slice!(range) ⇒ nil

    Returns:

    • (nil) 


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# File 'array.c', line 1953

static VALUE
rb_ary_slice_bang(argc, argv, ary)
int argc;

#sort ⇒ Array #sort {|a, b| ... } ⇒ Array

Returns a new array created by sorting self. Comparisons for the sort will be done using the <=> operator or using an optional code block. The block implements a comparison between a and b, returning -1, 0, or +1. See also Enumerable#sort_by.

a = [ "d", "a", "e", "c", "b" ]
a.sort                    #=> ["a", "b", "c", "d", "e"]
a.sort {|x,y| y <=> x }   #=> ["e", "d", "c", "b", "a"]

Overloads:



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# File 'array.c', line 1676

VALUE
rb_ary_sort(ary)
VALUE ary;

#sort! ⇒ Array #sort! {|a, b| ... } ⇒ Array

Sorts self. Comparisons for the sort will be done using the <=> operator or using an optional code block. The block implements a comparison between a and b, returning -1, 0, or +1. See also Enumerable#sort_by.

a = [ "d", "a", "e", "c", "b" ]
a.sort                    #=> ["a", "b", "c", "d", "e"]
a.sort {|x,y| y <=> x }   #=> ["e", "d", "c", "b", "a"]

Overloads:



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# File 'array.c', line 1648

VALUE
rb_ary_sort_bang(ary)
VALUE ary;

#to_a ⇒ Array

Returns self. If called on a subclass of Array, converts the receiver to an Array object.

Returns:



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# File 'array.c', line 1476

static VALUE
rb_ary_to_a(ary)
VALUE ary;

#to_ary ⇒ Array

Returns self.

Returns:



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# File 'array.c', line 1495

static VALUE
rb_ary_to_ary_m(ary)
VALUE ary;

#to_s ⇒ String

Returns self.join.

[ "a", "e", "i", "o" ].to_s   #=> "aeio"

Returns:



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# File 'array.c', line 1341

VALUE
rb_ary_to_s(ary)
VALUE ary;

#transpose ⇒ Array

Assumes that self is an array of arrays and transposes the rows and columns.

a = [[1,2], [3,4], [5,6]]
a.transpose   #=> [[1, 3, 5], [2, 4, 6]]

Returns:



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# File 'array.c', line 2121

static VALUE
rb_ary_transpose(ary)
VALUE ary;

#uniq ⇒ Array

Returns a new array by removing duplicate values in self.

a = [ "a", "a", "b", "b", "c" ]
a.uniq   #=> ["a", "b", "c"]

Returns:



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# File 'array.c', line 2783

static VALUE
rb_ary_uniq(ary)
VALUE ary;

#uniq! ⇒ Array?

Removes duplicate elements from self. Returns nil if no changes are made (that is, no duplicates are found).

a = [ "a", "a", "b", "b", "c" ]
a.uniq!   #=> ["a", "b", "c"]
b = [ "a", "b", "c" ]
b.uniq!   #=> nil

Returns:



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# File 'array.c', line 2750

static VALUE
rb_ary_uniq_bang(ary)
VALUE ary;

#unshift(obj, ...) ⇒ Array

Prepends objects to the front of array. other elements up one.

a = [ "b", "c", "d" ]
a.unshift("a")   #=> ["a", "b", "c", "d"]
a.unshift(1, 2)  #=> [ 1, 2, "a", "b", "c", "d"]

Returns:



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# File 'array.c', line 554

static VALUE
rb_ary_unshift_m(argc, argv, ary)
int argc;

#values_at(selector, ...) ⇒ Array

Returns an array containing the elements in self corresponding to the given selector(s). The selectors may be either integer indices or ranges. See also Array#select.

a = %w{ a b c d e f }
a.values_at(1, 3, 5)
a.values_at(1, 3, 5, 7)
a.values_at(-1, -3, -5, -7)
a.values_at(1..3, 2...5)

Returns:



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# File 'array.c', line 1793

static VALUE
rb_ary_values_at(argc, argv, ary)
int argc;

#zip(arg, ...) ⇒ Array #zip(arg, ...) {|arr| ... } ⇒ nil

Converts any arguments to arrays, then merges elements of self with corresponding elements from each argument. This generates a sequence of self.size n-element arrays, where n is one more that the count of arguments. If the size of any argument is less than enumObj.size, nil values are supplied. If a block given, it is invoked for each output array, otherwise an array of arrays is returned.

a = [ 4, 5, 6 ]
b = [ 7, 8, 9 ]

[1,2,3].zip(a, b)      #=> [[1, 4, 7], [2, 5, 8], [3, 6, 9]]
[1,2].zip(a,b)         #=> [[1, 4, 7], [2, 5, 8]]
a.zip([1,2],[8])       #=> [[4,1,8], [5,2,nil], [6,nil,nil]]

Overloads:

  • #zip(arg, ...) ⇒ Array

    Returns:

  • #zip(arg, ...) {|arr| ... } ⇒ nil

    Yields:

    • (arr)

    Returns:

    • (nil) 


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# File 'array.c', line 2071

static VALUE
rb_ary_zip(argc, argv, ary)
int argc;

#|(other_array) ⇒ Array

Set Union—Returns a new array by joining this array with other_array, removing duplicates.

[ "a", "b", "c" ] | [ "c", "d", "a" ]
       #=> [ "a", "b", "c", "d" ]

Returns:



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# File 'array.c', line 2709

static VALUE
rb_ary_or(ary1, ary2)
VALUE ary1, ary2;