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Wraps its argument in an array unless it is already an array (or array-like).
Specifically:
-
If the argument is
nil
an empty array is returned. -
Otherwise, if the argument responds to
to_ary
it is invoked, and its result returned. -
Otherwise, returns an array with the argument as its single element.
Array.wrap(nil) # => [] Array.wrap([1, 2, 3]) # => [1, 2, 3] Array.wrap(0) # => [0]
This method is similar in purpose to Kernel#Array
, but there are some differences:
-
If the argument responds to
to_ary
the method is invoked.Kernel#Array
moves on to tryto_a
if the returned value isnil
, butArray.wrap
returns an array with the argument as its single element right away. -
If the returned value from
to_ary
is neithernil
nor anArray
object,Kernel#Array
raises an exception, whileArray.wrap
does not, it just returns the value. -
It does not call
to_a
on the argument, if the argument does not respond toto_ary
it returns an array with the argument as its single element.
The last point is easily explained with some enumerables:
Array(foo: :bar) # => [[:foo, :bar]]
Array.wrap(foo: :bar) # => [{:foo=>:bar}]
There's also a related idiom that uses the splat operator:
[*object]
which returns []
for nil
, but calls to Array(object)
otherwise.
The differences with Kernel#Array
explained above apply to the rest of object
s.
Returns a deep copy of array.
array = [1, [2, 3]]
dup = array.deep_dup
dup[1][2] = 4
array[1][2] # => nil
dup[1][2] # => 4
Returns a copy of the Array
excluding the specified elements.
["David", "Rafael", "Aaron", "Todd"].excluding("Aaron", "Todd") # => ["David", "Rafael"]
[ [ 0, 1 ], [ 1, 0 ] ].excluding([ [ 1, 0 ] ]) # => [ [ 0, 1 ] ]
Note: This is an optimization of Enumerable#excluding
that uses Array#-
instead of Array#reject
for performance reasons.
Removes and returns the elements for which the block returns a true value. If no block is given, an Enumerator is returned instead.
numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
odd_numbers = numbers.extract! { |number| number.odd? } # => [1, 3, 5, 7, 9]
numbers # => [0, 2, 4, 6, 8]
Extracts options from a set of arguments. Removes and returns the last element in the array if it's a hash, otherwise returns a blank hash.
def options(*args)
args.extract_options!
end
options(1, 2) # => {}
options(1, 2, a: :b) # => {:a=>:b}
Equal to self[4]
.
%w( a b c d e ).fifth # => "e"
Equal to self[41]
. Also known as accessing “the reddit”.
(1..42).to_a.forty_two # => 42
Equal to self[3]
.
%w( a b c d e ).fourth # => "d"
Returns the tail of the array from position
.
%w( a b c d ).from(0) # => ["a", "b", "c", "d"]
%w( a b c d ).from(2) # => ["c", "d"]
%w( a b c d ).from(10) # => []
%w().from(0) # => []
%w( a b c d ).from(-2) # => ["c", "d"]
%w( a b c ).from(-10) # => []
Splits or iterates over the array in number
of groups, padding any remaining slots with fill_with
unless it is false
.
%w(1 2 3 4 5 6 7 8 9 10).in_groups(3) {|group| p group}
["1", "2", "3", "4"]
["5", "6", "7", nil]
["8", "9", "10", nil]
%w(1 2 3 4 5 6 7 8 9 10).in_groups(3, ' ') {|group| p group}
["1", "2", "3", "4"]
["5", "6", "7", " "]
["8", "9", "10", " "]
%w(1 2 3 4 5 6 7).in_groups(3, false) {|group| p group}
["1", "2", "3"]
["4", "5"]
["6", "7"]
# File activesupport/lib/active_support/core_ext/array/grouping.rb, line 62 def in_groups(number, fill_with = nil) # size.div number gives minor group size; # size % number gives how many objects need extra accommodation; # each group hold either division or division + 1 items. division = size.div number modulo = size % number # create a new array avoiding dup groups = [] start = 0 number.times do |index| length = division + (modulo > 0 && modulo > index ? 1 : 0) groups << last_group = slice(start, length) last_group << fill_with if fill_with != false && modulo > 0 && length == division start += length end if block_given? groups.each { |g| yield(g) } else groups end end
Splits or iterates over the array in groups of size number
, padding any remaining slots with fill_with
unless it is false
.
%w(1 2 3 4 5 6 7 8 9 10).in_groups_of(3) {|group| p group}
["1", "2", "3"]
["4", "5", "6"]
["7", "8", "9"]
["10", nil, nil]
%w(1 2 3 4 5).in_groups_of(2, ' ') {|group| p group}
["1", "2"]
["3", "4"]
["5", " "]
%w(1 2 3 4 5).in_groups_of(2, false) {|group| p group}
["1", "2"]
["3", "4"]
["5"]
# File activesupport/lib/active_support/core_ext/array/grouping.rb, line 22 def in_groups_of(number, fill_with = nil) if number.to_i <= 0 raise ArgumentError, "Group size must be a positive integer, was #{number.inspect}" end if fill_with == false collection = self else # size % number gives how many extra we have; # subtracting from number gives how many to add; # modulo number ensures we don't add group of just fill. padding = (number - size % number) % number collection = dup.concat(Array.new(padding, fill_with)) end if block_given? collection.each_slice(number) { |slice| yield(slice) } else collection.each_slice(number).to_a end end
Returns a new array that includes the passed elements.
[ 1, 2, 3 ].including(4, 5) # => [ 1, 2, 3, 4, 5 ]
[ [ 0, 1 ] ].including([ [ 1, 0 ] ]) # => [ [ 0, 1 ], [ 1, 0 ] ]
Wraps the array in an ArrayInquirer
object, which gives a friendlier way to check its string-like contents.
pets = [:cat, :dog].inquiry
pets.cat? # => true
pets.ferret? # => false
pets.any?(:cat, :ferret) # => true
pets.any?(:ferret, :alligator) # => false
Equal to self[1]
.
%w( a b c d e ).second # => "b"
Equal to self[-2]
.
%w( a b c d e ).second_to_last # => "d"
Divides the array into one or more subarrays based on a delimiting value
or the result of an optional block.
[1, 2, 3, 4, 5].split(3) # => [[1, 2], [4, 5]]
(1..10).to_a.split { |i| i % 3 == 0 } # => [[1, 2], [4, 5], [7, 8], [10]]
# File activesupport/lib/active_support/core_ext/array/grouping.rb, line 93 def split(value = nil) arr = dup result = [] if block_given? while (idx = arr.index { |i| yield i }) result << arr.shift(idx) arr.shift end else while (idx = arr.index(value)) result << arr.shift(idx) arr.shift end end result << arr end
Equal to self[2]
.
%w( a b c d e ).third # => "c"
Equal to self[-3]
.
%w( a b c d e ).third_to_last # => "c"
Returns the beginning of the array up to position
.
%w( a b c d ).to(0) # => ["a"]
%w( a b c d ).to(2) # => ["a", "b", "c"]
%w( a b c d ).to(10) # => ["a", "b", "c", "d"]
%w().to(0) # => []
%w( a b c d ).to(-2) # => ["a", "b", "c"]
%w( a b c ).to(-10) # => []
Extends Array#to_s
to convert a collection of elements into a comma separated id list if :db
argument is given as the format.
Blog.all.to_formatted_s(:db) # => "1,2,3"
Blog.none.to_formatted_s(:db) # => "null"
[1,2].to_formatted_s # => "[1, 2]"
Calls to_param
on all its elements and joins the result with slashes. This is used by url_for
in Action Pack.
Converts an array into a string suitable for use as a URL query string, using the given key
as the param name.
['Rails', 'coding'].to_query('hobbies') # => "hobbies%5B%5D=Rails&hobbies%5B%5D=coding"
Converts the array to a comma-separated sentence where the last element is joined by the connector word.
You can pass the following options to change the default behavior. If you pass an option key that doesn't exist in the list below, it will raise an ArgumentError
.
Options
-
:words_connector
- The sign or word used to join the elements in arrays with two or more elements (default: “, ”). -
:two_words_connector
- The sign or word used to join the elements in arrays with two elements (default: “ and ”). -
:last_word_connector
- The sign or word used to join the last element in arrays with three or more elements (default: “, and ”). -
:locale
- Ifi18n
is available, you can set a locale and use the connector options defined on the 'support.array' namespace in the corresponding dictionary file.
Examples
[].to_sentence # => ""
['one'].to_sentence # => "one"
['one', 'two'].to_sentence # => "one and two"
['one', 'two', 'three'].to_sentence # => "one, two, and three"
['one', 'two'].to_sentence(passing: 'invalid option')
# => ArgumentError: Unknown key: :passing. Valid keys are: :words_connector, :two_words_connector, :last_word_connector, :locale
['one', 'two'].to_sentence(two_words_connector: '-')
# => "one-two"
['one', 'two', 'three'].to_sentence(words_connector: ' or ', last_word_connector: ' or at least ')
# => "one or two or at least three"
Using :locale
option:
# Given this locale dictionary:
#
# es:
# support:
# array:
# words_connector: " o "
# two_words_connector: " y "
# last_word_connector: " o al menos "
['uno', 'dos'].to_sentence(locale: :es)
# => "uno y dos"
['uno', 'dos', 'tres'].to_sentence(locale: :es)
# => "uno o dos o al menos tres"
# File activesupport/lib/active_support/core_ext/array/conversions.rb, line 61 def to_sentence(options = {}) options.assert_valid_keys(:words_connector, :two_words_connector, :last_word_connector, :locale) default_connectors = { words_connector: ", ", two_words_connector: " and ", last_word_connector: ", and " } if defined?(I18n) i18n_connectors = I18n.translate(:'support.array', locale: options[:locale], default: {}) default_connectors.merge!(i18n_connectors) end options = default_connectors.merge!(options) case length when 0 "" when 1 "#{self[0]}" when 2 "#{self[0]}#{options[:two_words_connector]}#{self[1]}" else "#{self[0...-1].join(options[:words_connector])}#{options[:last_word_connector]}#{self[-1]}" end end
Returns a string that represents the array in XML by invoking to_xml
on each element. Active Record collections delegate their representation in XML to this method.
All elements are expected to respond to to_xml
, if any of them does not then an exception is raised.
The root node reflects the class name of the first element in plural if all elements belong to the same type and that's not Hash:
customer.projects.to_xml
<?xml version="1.0" encoding="UTF-8"?>
<projects type="array">
<project>
<amount type="decimal">20000.0</amount>
<customer-id type="integer">1567</customer-id>
<deal-date type="date">2008-04-09</deal-date>
...
</project>
<project>
<amount type="decimal">57230.0</amount>
<customer-id type="integer">1567</customer-id>
<deal-date type="date">2008-04-15</deal-date>
...
</project>
</projects>
Otherwise the root element is “objects”:
[{ foo: 1, bar: 2}, { baz: 3}].to_xml
<?xml version="1.0" encoding="UTF-8"?>
<objects type="array">
<object>
<bar type="integer">2</bar>
<foo type="integer">1</foo>
</object>
<object>
<baz type="integer">3</baz>
</object>
</objects>
If the collection is empty the root element is “nil-classes” by default:
[].to_xml
<?xml version="1.0" encoding="UTF-8"?>
<nil-classes type="array"/>
To ensure a meaningful root element use the :root
option:
customer_with_no_projects.projects.to_xml(root: 'projects')
<?xml version="1.0" encoding="UTF-8"?>
<projects type="array"/>
By default name of the node for the children of root is root.singularize
. You can change it with the :children
option.
The options
hash is passed downwards:
Message.all.to_xml(skip_types: true)
<?xml version="1.0" encoding="UTF-8"?>
<messages>
<message>
<created-at>2008-03-07T09:58:18+01:00</created-at>
<id>1</id>
<name>1</name>
<updated-at>2008-03-07T09:58:18+01:00</updated-at>
<user-id>1</user-id>
</message>
</messages>
# File activesupport/lib/active_support/core_ext/array/conversions.rb, line 183 def to_xml(options = {}) require "active_support/builder" unless defined?(Builder) options = options.dup options[:indent] ||= 2 options[:builder] ||= Builder::XmlMarkup.new(indent: options[:indent]) options[:root] ||= \ if first.class != Hash && all? { |e| e.is_a?(first.class) } underscored = ActiveSupport::Inflector.underscore(first.class.name) ActiveSupport::Inflector.pluralize(underscored).tr("/", "_") else "objects" end builder = options[:builder] builder.instruct! unless options.delete(:skip_instruct) root = ActiveSupport::XmlMini.rename_key(options[:root].to_s, options) children = options.delete(:children) || root.singularize attributes = options[:skip_types] ? {} : { type: "array" } if empty? builder.tag!(root, attributes) else builder.tag!(root, attributes) do each { |value| ActiveSupport::XmlMini.to_tag(children, value, options) } yield builder if block_given? end end end