src/classes/Array.html

---
title: Array
layout: default
---
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            <span>Ruby on Rails 8.0.0</span><br />
        
        <div class="type">Class</div>
        <h1>
            Array
            
                <span class="parent">&lt;
                    
                    <a href="Object.html">Object</a>
                    
                </span>
            
        </h1>
        <ul class="files">
            
            <li><a href="../files/activesupport/lib/active_support/core_ext/array/access_rb.html">activesupport/lib/active_support/core_ext/array/access.rb</a></li>
            
            <li><a href="../files/activesupport/lib/active_support/core_ext/array/conversions_rb.html">activesupport/lib/active_support/core_ext/array/conversions.rb</a></li>
            
            <li><a href="../files/activesupport/lib/active_support/core_ext/array/extract_rb.html">activesupport/lib/active_support/core_ext/array/extract.rb</a></li>
            
            <li><a href="../files/activesupport/lib/active_support/core_ext/array/extract_options_rb.html">activesupport/lib/active_support/core_ext/array/extract_options.rb</a></li>
            
            <li><a href="../files/activesupport/lib/active_support/core_ext/array/grouping_rb.html">activesupport/lib/active_support/core_ext/array/grouping.rb</a></li>
            
            <li><a href="../files/activesupport/lib/active_support/core_ext/array/inquiry_rb.html">activesupport/lib/active_support/core_ext/array/inquiry.rb</a></li>
            
            <li><a href="../files/activesupport/lib/active_support/core_ext/array/wrap_rb.html">activesupport/lib/active_support/core_ext/array/wrap.rb</a></li>
            
            <li><a href="../files/activesupport/lib/active_support/core_ext/enumerable_rb.html">activesupport/lib/active_support/core_ext/enumerable.rb</a></li>
            
            <li><a href="../files/activesupport/lib/active_support/core_ext/object/blank_rb.html">activesupport/lib/active_support/core_ext/object/blank.rb</a></li>
            
            <li><a href="../files/activesupport/lib/active_support/core_ext/object/deep_dup_rb.html">activesupport/lib/active_support/core_ext/object/deep_dup.rb</a></li>
            
            <li><a href="../files/activesupport/lib/active_support/core_ext/object/json_rb.html">activesupport/lib/active_support/core_ext/object/json.rb</a></li>
            
            <li><a href="../files/activesupport/lib/active_support/core_ext/object/to_query_rb.html">activesupport/lib/active_support/core_ext/object/to_query.rb</a></li>
            
        </ul>
    </div>
    <div id="bodyContent">
        <div id="content">
  

    <h2 id="methods">Methods</h2>
    <ul>
      
        <li>
          <a href="#method-i-deep_dup">deep_dup</a>
        </li>
      
        <li>
          <a href="#method-i-excluding">excluding</a>
        </li>
      
        <li>
          <a href="#method-i-extract-21">extract!</a>
        </li>
      
        <li>
          <a href="#method-i-extract_options-21">extract_options!</a>
        </li>
      
        <li>
          <a href="#method-i-fifth">fifth</a>
        </li>
      
        <li>
          <a href="#method-i-forty_two">forty_two</a>
        </li>
      
        <li>
          <a href="#method-i-fourth">fourth</a>
        </li>
      
        <li>
          <a href="#method-i-from">from</a>
        </li>
      
        <li>
          <a href="#method-i-in_groups">in_groups</a>
        </li>
      
        <li>
          <a href="#method-i-in_groups_of">in_groups_of</a>
        </li>
      
        <li>
          <a href="#method-i-including">including</a>
        </li>
      
        <li>
          <a href="#method-i-inquiry">inquiry</a>
        </li>
      
        <li>
          <a href="#method-i-second">second</a>
        </li>
      
        <li>
          <a href="#method-i-second_to_last">second_to_last</a>
        </li>
      
        <li>
          <a href="#method-i-split">split</a>
        </li>
      
        <li>
          <a href="#method-i-third">third</a>
        </li>
      
        <li>
          <a href="#method-i-third_to_last">third_to_last</a>
        </li>
      
        <li>
          <a href="#method-i-to">to</a>
        </li>
      
        <li>
          <a href="#method-i-to_formatted_s">to_formatted_s</a>
        </li>
      
        <li>
          <a href="#method-i-to_fs">to_fs</a>
        </li>
      
        <li>
          <a href="#method-i-to_param">to_param</a>
        </li>
      
        <li>
          <a href="#method-i-to_query">to_query</a>
        </li>
      
        <li>
          <a href="#method-i-to_sentence">to_sentence</a>
        </li>
      
        <li>
          <a href="#method-i-to_xml">to_xml</a>
        </li>
      
        <li>
          <a href="#method-i-without">without</a>
        </li>
      
        <li>
          <a href="#method-c-wrap">wrap</a>
        </li>
      
    </ul>
  

    <!-- Methods -->
    
      <h2 id="class-public-methods">Class Public methods</h2>
      
        <div class="method">
          <h3 id="method-c-wrap">
            
              wrap(object)
            
          </h3>

          
            <div class="description">
              <p>Wraps its argument in an array unless it is already an array (or array-like).</p>

<p>Specifically:</p>
<ul><li>
<p>If the argument is <code>nil</code> an empty array is returned.</p>
</li><li>
<p>Otherwise, if the argument responds to <code>to_ary</code> it is invoked, and its result returned.</p>
</li><li>
<p>Otherwise, returns an array with the argument as its single element.</p>

<pre><code>Array.wrap(nil)       # =&gt; []
Array.wrap([1, 2, 3]) # =&gt; [1, 2, 3]
Array.wrap(0)         # =&gt; [0]
</code></pre>
</li></ul>

<p>This method is similar in purpose to <code>Kernel#Array</code>, but there are some differences:</p>
<ul><li>
<p>If the argument responds to <code>to_ary</code> the method is invoked. <code>Kernel#Array</code> moves on to try <code>to_a</code> if the returned value is <code>nil</code>, but <code>Array.wrap</code> returns an array with the argument as its single element right away.</p>
</li><li>
<p>If the returned value from <code>to_ary</code> is neither <code>nil</code> nor an <code>Array</code> object, <code>Kernel#Array</code> raises an exception, while <code>Array.wrap</code> does not, it just returns the value.</p>
</li><li>
<p>It does not call <code>to_a</code> on the argument, if the argument does not respond to <code>to_ary</code> it returns an array with the argument as its single element.</p>
</li></ul>

<p>The last point is easily explained with some enumerables:</p>

<pre><code>Array(foo: :bar)      # =&gt; [[:foo, :bar]]
Array.wrap(foo: :bar) # =&gt; [{:foo=&gt;:bar}]
</code></pre>

<p>There’s also a related idiom that uses the splat operator:</p>

<pre><code>[*object]
</code></pre>

<p>which returns <code>[]</code> for <code>nil</code>, but calls to <code>Array(object)</code> otherwise.</p>

<p>The differences with <code>Kernel#Array</code> explained above apply to the rest of <code>object</code>s.</p>
            </div>
          

            <details class="method__source">
              <summary>
                <span class="label">📝 Source code</span>
              </summary>

              <pre><code class="ruby"># File activesupport/lib/active_support/core_ext/array/wrap.rb, line 39
  def self.wrap(object)
    if object.nil?
      []
    elsif object.respond_to?(:to_ary)
      object.to_ary || [object]
    else
      [object]
    end
  end</code></pre>
              
                <a href="https://github.com/rails/rails/blob/dd8f7185faeca6ee968a6e9367f6d8601a83b8db/activesupport/lib/active_support/core_ext/array/wrap.rb#L39" target="_blank" class="github_url">🔎 See on GitHub</a>
              
            </details>
          
        </div>
        
      
      <h2 id="instance-public-methods">Instance Public methods</h2>
      
        <div class="method">
          <h3 id="method-i-deep_dup">
            
              deep_dup()
            
          </h3>

          
            <div class="description">
              <p>Returns a deep copy of array.</p>

<pre><code>array = [1, [2, 3]]
dup   = array.deep_dup
dup[1][2] = 4

array[1][2] # =&gt; nil
dup[1][2]   # =&gt; 4
</code></pre>
            </div>
          

            <details class="method__source">
              <summary>
                <span class="label">📝 Source code</span>
              </summary>

              <pre><code class="ruby"># File activesupport/lib/active_support/core_ext/object/deep_dup.rb, line 29
  def deep_dup
    map(&amp;:deep_dup)
  end</code></pre>
              
                <a href="https://github.com/rails/rails/blob/dd8f7185faeca6ee968a6e9367f6d8601a83b8db/activesupport/lib/active_support/core_ext/object/deep_dup.rb#L29" target="_blank" class="github_url">🔎 See on GitHub</a>
              
            </details>
          
        </div>
        
        <div class="method">
          <h3 id="method-i-excluding">
            
              excluding(*elements)
            
          </h3>

          
            <div class="description">
              <p>Returns a copy of the <a href="Array.html"><code>Array</code></a> excluding the specified elements.</p>

<pre><code>[&quot;David&quot;, &quot;Rafael&quot;, &quot;Aaron&quot;, &quot;Todd&quot;].excluding(&quot;Aaron&quot;, &quot;Todd&quot;) # =&gt; [&quot;David&quot;, &quot;Rafael&quot;]
[ [ 0, 1 ], [ 1, 0 ] ].excluding([ [ 1, 0 ] ]) # =&gt; [ [ 0, 1 ] ]
</code></pre>

<p>Note: This is an optimization of <code>Enumerable#excluding</code> that uses <code>Array#-</code> instead of <code>Array#reject</code> for performance reasons.</p>
            </div>
          

            <div class="aka">
              Also aliased as: <a href="Array.html#method-i-without">without</a>
            </div>
          

            <details class="method__source">
              <summary>
                <span class="label">📝 Source code</span>
              </summary>

              <pre><code class="ruby"># File activesupport/lib/active_support/core_ext/array/access.rb, line 47
  def excluding(*elements)
    self - elements.flatten(1)
  end</code></pre>
              
                <a href="https://github.com/rails/rails/blob/dd8f7185faeca6ee968a6e9367f6d8601a83b8db/activesupport/lib/active_support/core_ext/array/access.rb#L47" target="_blank" class="github_url">🔎 See on GitHub</a>
              
            </details>
          
        </div>
        
        <div class="method">
          <h3 id="method-i-extract-21">
            
              extract!()
            
          </h3>

          
            <div class="description">
              <p>Removes and returns the elements for which the block returns a true value. If no block is given, an Enumerator is returned instead.</p>

<pre><code>numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
odd_numbers = numbers.extract! { |number| number.odd? } # =&gt; [1, 3, 5, 7, 9]
numbers # =&gt; [0, 2, 4, 6, 8]
</code></pre>
            </div>
          

            <details class="method__source">
              <summary>
                <span class="label">📝 Source code</span>
              </summary>

              <pre><code class="ruby"># File activesupport/lib/active_support/core_ext/array/extract.rb, line 10
  def extract!
    return to_enum(:extract!) { size } unless block_given?

    extracted_elements = []

    reject! do |element|
      extracted_elements &lt;&lt; element if yield(element)
    end

    extracted_elements
  end</code></pre>
              
                <a href="https://github.com/rails/rails/blob/dd8f7185faeca6ee968a6e9367f6d8601a83b8db/activesupport/lib/active_support/core_ext/array/extract.rb#L10" target="_blank" class="github_url">🔎 See on GitHub</a>
              
            </details>
          
        </div>
        
        <div class="method">
          <h3 id="method-i-extract_options-21">
            
              extract_options!()
            
          </h3>

          
            <div class="description">
              <p>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.</p>

<pre><code>def options(*args)
  args.extract_options!
end

options(1, 2)        # =&gt; {}
options(1, 2, a: :b) # =&gt; {:a=&gt;:b}
</code></pre>
            </div>
          

            <details class="method__source">
              <summary>
                <span class="label">📝 Source code</span>
              </summary>

              <pre><code class="ruby"># File activesupport/lib/active_support/core_ext/array/extract_options.rb, line 24
  def extract_options!
    if last.is_a?(Hash) &amp;&amp; last.extractable_options?
      pop
    else
      {}
    end
  end</code></pre>
              
                <a href="https://github.com/rails/rails/blob/dd8f7185faeca6ee968a6e9367f6d8601a83b8db/activesupport/lib/active_support/core_ext/array/extract_options.rb#L24" target="_blank" class="github_url">🔎 See on GitHub</a>
              
            </details>
          
        </div>
        
        <div class="method">
          <h3 id="method-i-fifth">
            
              fifth()
            
          </h3>

          
            <div class="description">
              <p>Equal to <code>self[4]</code>.</p>

<pre><code>%w( a b c d e ).fifth # =&gt; &quot;e&quot;
</code></pre>
            </div>
          

            <details class="method__source">
              <summary>
                <span class="label">📝 Source code</span>
              </summary>

              <pre><code class="ruby"># File activesupport/lib/active_support/core_ext/array/access.rb, line 76
  def fifth
    self[4]
  end</code></pre>
              
                <a href="https://github.com/rails/rails/blob/dd8f7185faeca6ee968a6e9367f6d8601a83b8db/activesupport/lib/active_support/core_ext/array/access.rb#L76" target="_blank" class="github_url">🔎 See on GitHub</a>
              
            </details>
          
        </div>
        
        <div class="method">
          <h3 id="method-i-forty_two">
            
              forty_two()
            
          </h3>

          
            <div class="description">
              <p>Equal to <code>self[41]</code>. Also known as accessing “the reddit”.</p>

<pre><code>(1..42).to_a.forty_two # =&gt; 42
</code></pre>
            </div>
          

            <details class="method__source">
              <summary>
                <span class="label">📝 Source code</span>
              </summary>

              <pre><code class="ruby"># File activesupport/lib/active_support/core_ext/array/access.rb, line 83
  def forty_two
    self[41]
  end</code></pre>
              
                <a href="https://github.com/rails/rails/blob/dd8f7185faeca6ee968a6e9367f6d8601a83b8db/activesupport/lib/active_support/core_ext/array/access.rb#L83" target="_blank" class="github_url">🔎 See on GitHub</a>
              
            </details>
          
        </div>
        
        <div class="method">
          <h3 id="method-i-fourth">
            
              fourth()
            
          </h3>

          
            <div class="description">
              <p>Equal to <code>self[3]</code>.</p>

<pre><code>%w( a b c d e ).fourth # =&gt; &quot;d&quot;
</code></pre>
            </div>
          

            <details class="method__source">
              <summary>
                <span class="label">📝 Source code</span>
              </summary>

              <pre><code class="ruby"># File activesupport/lib/active_support/core_ext/array/access.rb, line 69
  def fourth
    self[3]
  end</code></pre>
              
                <a href="https://github.com/rails/rails/blob/dd8f7185faeca6ee968a6e9367f6d8601a83b8db/activesupport/lib/active_support/core_ext/array/access.rb#L69" target="_blank" class="github_url">🔎 See on GitHub</a>
              
            </details>
          
        </div>
        
        <div class="method">
          <h3 id="method-i-from">
            
              from(position)
            
          </h3>

          
            <div class="description">
              <p>Returns the tail of the array from <code>position</code>.</p>

<pre><code>%w( a b c d ).from(0)  # =&gt; [&quot;a&quot;, &quot;b&quot;, &quot;c&quot;, &quot;d&quot;]
%w( a b c d ).from(2)  # =&gt; [&quot;c&quot;, &quot;d&quot;]
%w( a b c d ).from(10) # =&gt; []
%w().from(0)           # =&gt; []
%w( a b c d ).from(-2) # =&gt; [&quot;c&quot;, &quot;d&quot;]
%w( a b c ).from(-10)  # =&gt; []
</code></pre>
            </div>
          

            <details class="method__source">
              <summary>
                <span class="label">📝 Source code</span>
              </summary>

              <pre><code class="ruby"># File activesupport/lib/active_support/core_ext/array/access.rb, line 12
  def from(position)
    self[position, length] || []
  end</code></pre>
              
                <a href="https://github.com/rails/rails/blob/dd8f7185faeca6ee968a6e9367f6d8601a83b8db/activesupport/lib/active_support/core_ext/array/access.rb#L12" target="_blank" class="github_url">🔎 See on GitHub</a>
              
            </details>
          
        </div>
        
        <div class="method">
          <h3 id="method-i-in_groups">
            
              in_groups(number, fill_with = nil, &amp;block)
            
          </h3>

          
            <div class="description">
              <p>Splits or iterates over the array in <code>number</code> of groups, padding any remaining slots with <code>fill_with</code> unless it is <code>false</code>.</p>

<pre><code>%w(1 2 3 4 5 6 7 8 9 10).in_groups(3) {|group| p group}
[&quot;1&quot;, &quot;2&quot;, &quot;3&quot;, &quot;4&quot;]
[&quot;5&quot;, &quot;6&quot;, &quot;7&quot;, nil]
[&quot;8&quot;, &quot;9&quot;, &quot;10&quot;, nil]

%w(1 2 3 4 5 6 7 8 9 10).in_groups(3, &#39;&amp;nbsp;&#39;) {|group| p group}
[&quot;1&quot;, &quot;2&quot;, &quot;3&quot;, &quot;4&quot;]
[&quot;5&quot;, &quot;6&quot;, &quot;7&quot;, &quot;&amp;nbsp;&quot;]
[&quot;8&quot;, &quot;9&quot;, &quot;10&quot;, &quot;&amp;nbsp;&quot;]

%w(1 2 3 4 5 6 7).in_groups(3, false) {|group| p group}
[&quot;1&quot;, &quot;2&quot;, &quot;3&quot;]
[&quot;4&quot;, &quot;5&quot;]
[&quot;6&quot;, &quot;7&quot;]
</code></pre>
            </div>
          

            <details class="method__source">
              <summary>
                <span class="label">📝 Source code</span>
              </summary>

              <pre><code class="ruby"># File activesupport/lib/active_support/core_ext/array/grouping.rb, line 62
  def in_groups(number, fill_with = nil, &amp;block)
    # 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 &gt; 0 &amp;&amp; modulo &gt; index ? 1 : 0)
      groups &lt;&lt; last_group = slice(start, length)
      last_group &lt;&lt; fill_with if fill_with != false &amp;&amp;
        modulo &gt; 0 &amp;&amp; length == division
      start += length
    end

    if block_given?
      groups.each(&amp;block)
    else
      groups
    end
  end</code></pre>
              
                <a href="https://github.com/rails/rails/blob/dd8f7185faeca6ee968a6e9367f6d8601a83b8db/activesupport/lib/active_support/core_ext/array/grouping.rb#L62" target="_blank" class="github_url">🔎 See on GitHub</a>
              
            </details>
          
        </div>
        
        <div class="method">
          <h3 id="method-i-in_groups_of">
            
              in_groups_of(number, fill_with = nil, &amp;block)
            
          </h3>

          
            <div class="description">
              <p>Splits or iterates over the array in groups of size <code>number</code>, padding any remaining slots with <code>fill_with</code> unless it is <code>false</code>.</p>

<pre><code>%w(1 2 3 4 5 6 7 8 9 10).in_groups_of(3) {|group| p group}
[&quot;1&quot;, &quot;2&quot;, &quot;3&quot;]
[&quot;4&quot;, &quot;5&quot;, &quot;6&quot;]
[&quot;7&quot;, &quot;8&quot;, &quot;9&quot;]
[&quot;10&quot;, nil, nil]

%w(1 2 3 4 5).in_groups_of(2, &#39;&amp;nbsp;&#39;) {|group| p group}
[&quot;1&quot;, &quot;2&quot;]
[&quot;3&quot;, &quot;4&quot;]
[&quot;5&quot;, &quot;&amp;nbsp;&quot;]

%w(1 2 3 4 5).in_groups_of(2, false) {|group| p group}
[&quot;1&quot;, &quot;2&quot;]
[&quot;3&quot;, &quot;4&quot;]
[&quot;5&quot;]
</code></pre>
            </div>
          

            <details class="method__source">
              <summary>
                <span class="label">📝 Source code</span>
              </summary>

              <pre><code class="ruby"># File activesupport/lib/active_support/core_ext/array/grouping.rb, line 22
  def in_groups_of(number, fill_with = nil, &amp;block)
    if number.to_i &lt;= 0
      raise ArgumentError,
        &quot;Group size must be a positive integer, was #{number.inspect}&quot;
    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&#39;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, &amp;block)
    else
      collection.each_slice(number).to_a
    end
  end</code></pre>
              
                <a href="https://github.com/rails/rails/blob/dd8f7185faeca6ee968a6e9367f6d8601a83b8db/activesupport/lib/active_support/core_ext/array/grouping.rb#L22" target="_blank" class="github_url">🔎 See on GitHub</a>
              
            </details>
          
        </div>
        
        <div class="method">
          <h3 id="method-i-including">
            
              including(*elements)
            
          </h3>

          
            <div class="description">
              <p>Returns a new array that includes the passed elements.</p>

<pre><code>[ 1, 2, 3 ].including(4, 5) # =&gt; [ 1, 2, 3, 4, 5 ]
[ [ 0, 1 ] ].including([ [ 1, 0 ] ]) # =&gt; [ [ 0, 1 ], [ 1, 0 ] ]
</code></pre>
            </div>
          

            <details class="method__source">
              <summary>
                <span class="label">📝 Source code</span>
              </summary>

              <pre><code class="ruby"># File activesupport/lib/active_support/core_ext/array/access.rb, line 36
  def including(*elements)
    self + elements.flatten(1)
  end</code></pre>
              
                <a href="https://github.com/rails/rails/blob/dd8f7185faeca6ee968a6e9367f6d8601a83b8db/activesupport/lib/active_support/core_ext/array/access.rb#L36" target="_blank" class="github_url">🔎 See on GitHub</a>
              
            </details>
          
        </div>
        
        <div class="method">
          <h3 id="method-i-inquiry">
            
              inquiry()
            
          </h3>

          
            <div class="description">
              <p>Wraps the array in an <a href="ActiveSupport/ArrayInquirer.html"><code>ActiveSupport::ArrayInquirer</code></a> object, which gives a friendlier way to check its string-like contents.</p>

<pre><code>pets = [:cat, :dog].inquiry

pets.cat?     # =&gt; true
pets.ferret?  # =&gt; false

pets.any?(:cat, :ferret)  # =&gt; true
pets.any?(:ferret, :alligator)  # =&gt; false
</code></pre>
            </div>
          

            <details class="method__source">
              <summary>
                <span class="label">📝 Source code</span>
              </summary>

              <pre><code class="ruby"># File activesupport/lib/active_support/core_ext/array/inquiry.rb, line 16
  def inquiry
    ActiveSupport::ArrayInquirer.new(self)
  end</code></pre>
              
                <a href="https://github.com/rails/rails/blob/dd8f7185faeca6ee968a6e9367f6d8601a83b8db/activesupport/lib/active_support/core_ext/array/inquiry.rb#L16" target="_blank" class="github_url">🔎 See on GitHub</a>
              
            </details>
          
        </div>
        
        <div class="method">
          <h3 id="method-i-second">
            
              second()
            
          </h3>

          
            <div class="description">
              <p>Equal to <code>self[1]</code>.</p>

<pre><code>%w( a b c d e ).second # =&gt; &quot;b&quot;
</code></pre>
            </div>
          

            <details class="method__source">
              <summary>
                <span class="label">📝 Source code</span>
              </summary>

              <pre><code class="ruby"># File activesupport/lib/active_support/core_ext/array/access.rb, line 55
  def second
    self[1]
  end</code></pre>
              
                <a href="https://github.com/rails/rails/blob/dd8f7185faeca6ee968a6e9367f6d8601a83b8db/activesupport/lib/active_support/core_ext/array/access.rb#L55" target="_blank" class="github_url">🔎 See on GitHub</a>
              
            </details>
          
        </div>
        
        <div class="method">
          <h3 id="method-i-second_to_last">
            
              second_to_last()
            
          </h3>

          
            <div class="description">
              <p>Equal to <code>self[-2]</code>.</p>

<pre><code>%w( a b c d e ).second_to_last # =&gt; &quot;d&quot;
</code></pre>
            </div>
          

            <details class="method__source">
              <summary>
                <span class="label">📝 Source code</span>
              </summary>

              <pre><code class="ruby"># File activesupport/lib/active_support/core_ext/array/access.rb, line 97
  def second_to_last
    self[-2]
  end</code></pre>
              
                <a href="https://github.com/rails/rails/blob/dd8f7185faeca6ee968a6e9367f6d8601a83b8db/activesupport/lib/active_support/core_ext/array/access.rb#L97" target="_blank" class="github_url">🔎 See on GitHub</a>
              
            </details>
          
        </div>
        
        <div class="method">
          <h3 id="method-i-split">
            
              split(value = nil, &amp;block)
            
          </h3>

          
            <div class="description">
              <p>Divides the array into one or more subarrays based on a delimiting <code>value</code> or the result of an optional block.</p>

<pre><code>[1, 2, 3, 4, 5].split(3)              # =&gt; [[1, 2], [4, 5]]
(1..10).to_a.split { |i| i % 3 == 0 } # =&gt; [[1, 2], [4, 5], [7, 8], [10]]
</code></pre>
            </div>
          

            <details class="method__source">
              <summary>
                <span class="label">📝 Source code</span>
              </summary>

              <pre><code class="ruby"># File activesupport/lib/active_support/core_ext/array/grouping.rb, line 93
  def split(value = nil, &amp;block)
    arr = dup
    result = []
    if block_given?
      while (idx = arr.index(&amp;block))
        result &lt;&lt; arr.shift(idx)
        arr.shift
      end
    else
      while (idx = arr.index(value))
        result &lt;&lt; arr.shift(idx)
        arr.shift
      end
    end
    result &lt;&lt; arr
  end</code></pre>
              
                <a href="https://github.com/rails/rails/blob/dd8f7185faeca6ee968a6e9367f6d8601a83b8db/activesupport/lib/active_support/core_ext/array/grouping.rb#L93" target="_blank" class="github_url">🔎 See on GitHub</a>
              
            </details>
          
        </div>
        
        <div class="method">
          <h3 id="method-i-third">
            
              third()
            
          </h3>

          
            <div class="description">
              <p>Equal to <code>self[2]</code>.</p>

<pre><code>%w( a b c d e ).third # =&gt; &quot;c&quot;
</code></pre>
            </div>
          

            <details class="method__source">
              <summary>
                <span class="label">📝 Source code</span>
              </summary>

              <pre><code class="ruby"># File activesupport/lib/active_support/core_ext/array/access.rb, line 62
  def third
    self[2]
  end</code></pre>
              
                <a href="https://github.com/rails/rails/blob/dd8f7185faeca6ee968a6e9367f6d8601a83b8db/activesupport/lib/active_support/core_ext/array/access.rb#L62" target="_blank" class="github_url">🔎 See on GitHub</a>
              
            </details>
          
        </div>
        
        <div class="method">
          <h3 id="method-i-third_to_last">
            
              third_to_last()
            
          </h3>

          
            <div class="description">
              <p>Equal to <code>self[-3]</code>.</p>

<pre><code>%w( a b c d e ).third_to_last # =&gt; &quot;c&quot;
</code></pre>
            </div>
          

            <details class="method__source">
              <summary>
                <span class="label">📝 Source code</span>
              </summary>

              <pre><code class="ruby"># File activesupport/lib/active_support/core_ext/array/access.rb, line 90
  def third_to_last
    self[-3]
  end</code></pre>
              
                <a href="https://github.com/rails/rails/blob/dd8f7185faeca6ee968a6e9367f6d8601a83b8db/activesupport/lib/active_support/core_ext/array/access.rb#L90" target="_blank" class="github_url">🔎 See on GitHub</a>
              
            </details>
          
        </div>
        
        <div class="method">
          <h3 id="method-i-to">
            
              to(position)
            
          </h3>

          
            <div class="description">
              <p>Returns the beginning of the array up to <code>position</code>.</p>

<pre><code>%w( a b c d ).to(0)  # =&gt; [&quot;a&quot;]
%w( a b c d ).to(2)  # =&gt; [&quot;a&quot;, &quot;b&quot;, &quot;c&quot;]
%w( a b c d ).to(10) # =&gt; [&quot;a&quot;, &quot;b&quot;, &quot;c&quot;, &quot;d&quot;]
%w().to(0)           # =&gt; []
%w( a b c d ).to(-2) # =&gt; [&quot;a&quot;, &quot;b&quot;, &quot;c&quot;]
%w( a b c ).to(-10)  # =&gt; []
</code></pre>
            </div>
          

            <details class="method__source">
              <summary>
                <span class="label">📝 Source code</span>
              </summary>

              <pre><code class="ruby"># File activesupport/lib/active_support/core_ext/array/access.rb, line 24
  def to(position)
    if position &gt;= 0
      take position + 1
    else
      self[0..position]
    end
  end</code></pre>
              
                <a href="https://github.com/rails/rails/blob/dd8f7185faeca6ee968a6e9367f6d8601a83b8db/activesupport/lib/active_support/core_ext/array/access.rb#L24" target="_blank" class="github_url">🔎 See on GitHub</a>
              
            </details>
          
        </div>
        
        <div class="method">
          <h3 id="method-i-to_formatted_s">
            
              to_formatted_s(format = :default)
            
          </h3>

          
            <div class="description">
              
            </div>
          

            <div class="aka">
              Alias for: <a href="Array.html#method-i-to_fs">to_fs</a>
            </div>
          

        </div>
        
        <div class="method">
          <h3 id="method-i-to_fs">
            
              to_fs(format = :default)
            
          </h3>

          
            <div class="description">
              <p>Extends <code>Array#to_s</code> to convert a collection of elements into a comma separated id list if <code>:db</code> argument is given as the format.</p>

<p>This method is aliased to <code>to_formatted_s</code>.</p>

<pre><code>Blog.all.to_fs(:db)  # =&gt; &quot;1,2,3&quot;
Blog.none.to_fs(:db) # =&gt; &quot;null&quot;
[1,2].to_fs          # =&gt; &quot;[1, 2]&quot;
</code></pre>
            </div>
          

            <div class="aka">
              Also aliased as: <a href="Array.html#method-i-to_formatted_s">to_formatted_s</a>
            </div>
          

            <details class="method__source">
              <summary>
                <span class="label">📝 Source code</span>
              </summary>

              <pre><code class="ruby"># File activesupport/lib/active_support/core_ext/array/conversions.rb, line 94
  def to_fs(format = :default)
    case format
    when :db
      if empty?
        &quot;null&quot;
      else
        collect(&amp;:id).join(&quot;,&quot;)
      end
    else
      to_s
    end
  end</code></pre>
              
                <a href="https://github.com/rails/rails/blob/dd8f7185faeca6ee968a6e9367f6d8601a83b8db/activesupport/lib/active_support/core_ext/array/conversions.rb#L94" target="_blank" class="github_url">🔎 See on GitHub</a>
              
            </details>
          
        </div>
        
        <div class="method">
          <h3 id="method-i-to_param">
            
              to_param()
            
          </h3>

          
            <div class="description">
              <p>Calls <code>to_param</code> on all its elements and joins the result with slashes. This is used by <code>url_for</code> in Action Pack.</p>
            </div>
          

            <details class="method__source">
              <summary>
                <span class="label">📝 Source code</span>
              </summary>

              <pre><code class="ruby"># File activesupport/lib/active_support/core_ext/object/to_query.rb, line 42
  def to_param
    collect(&amp;:to_param).join &quot;/&quot;
  end</code></pre>
              
                <a href="https://github.com/rails/rails/blob/dd8f7185faeca6ee968a6e9367f6d8601a83b8db/activesupport/lib/active_support/core_ext/object/to_query.rb#L42" target="_blank" class="github_url">🔎 See on GitHub</a>
              
            </details>
          
        </div>
        
        <div class="method">
          <h3 id="method-i-to_query">
            
              to_query(key)
            
          </h3>

          
            <div class="description">
              <p>Converts an array into a string suitable for use as a URL query string, using the given <code>key</code> as the param name.</p>

<pre><code>[&#39;Rails&#39;, &#39;coding&#39;].to_query(&#39;hobbies&#39;) # =&gt; &quot;hobbies%5B%5D=Rails&amp;hobbies%5B%5D=coding&quot;
</code></pre>
            </div>
          

            <details class="method__source">
              <summary>
                <span class="label">📝 Source code</span>
              </summary>

              <pre><code class="ruby"># File activesupport/lib/active_support/core_ext/object/to_query.rb, line 50
  def to_query(key)
    prefix = &quot;#{key}[]&quot;

    if empty?
      nil.to_query(prefix)
    else
      collect { |value| value.to_query(prefix) }.join &quot;&amp;&quot;
    end
  end</code></pre>
              
                <a href="https://github.com/rails/rails/blob/dd8f7185faeca6ee968a6e9367f6d8601a83b8db/activesupport/lib/active_support/core_ext/object/to_query.rb#L50" target="_blank" class="github_url">🔎 See on GitHub</a>
              
            </details>
          
        </div>
        
        <div class="method">
          <h3 id="method-i-to_sentence">
            
              to_sentence(options = {})
            
          </h3>

          
            <div class="description">
              <p>Converts the array to a comma-separated sentence where the last element is joined by the connector word.</p>

<p>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 <code>ArgumentError</code>.</p>

<h4 id="method-i-to_sentence-label-Options">Options</h4>
<ul><li>
<p><code>:words_connector</code> - The sign or word used to join all but the last element in arrays with three or more elements (default: “, ”).</p>
</li><li>
<p><code>:last_word_connector</code> - The sign or word used to join the last element in arrays with three or more elements (default: “, and ”).</p>
</li><li>
<p><code>:two_words_connector</code> - The sign or word used to join the elements in arrays with two elements (default: “ and ”).</p>
</li><li>
<p><code>:locale</code> - If <code>i18n</code> is available, you can set a locale and use the connector options defined on the ‘support.array’ namespace in the corresponding dictionary file.</p>
</li></ul>

<h4 id="method-i-to_sentence-label-Examples">Examples</h4>

<pre><code>[].to_sentence                      # =&gt; &quot;&quot;
[&#39;one&#39;].to_sentence                 # =&gt; &quot;one&quot;
[&#39;one&#39;, &#39;two&#39;].to_sentence          # =&gt; &quot;one and two&quot;
[&#39;one&#39;, &#39;two&#39;, &#39;three&#39;].to_sentence # =&gt; &quot;one, two, and three&quot;

[&#39;one&#39;, &#39;two&#39;].to_sentence(passing: &#39;invalid option&#39;)
# =&gt; ArgumentError: Unknown key: :passing. Valid keys are: :words_connector, :two_words_connector, :last_word_connector, :locale

[&#39;one&#39;, &#39;two&#39;].to_sentence(two_words_connector: &#39;-&#39;)
# =&gt; &quot;one-two&quot;

[&#39;one&#39;, &#39;two&#39;, &#39;three&#39;].to_sentence(words_connector: &#39; or &#39;, last_word_connector: &#39; or at least &#39;)
# =&gt; &quot;one or two or at least three&quot;
</code></pre>

<p>Using <code>:locale</code> option:</p>

<pre><code># Given this locale dictionary:
#
#   es:
#     support:
#       array:
#         words_connector: &quot; o &quot;
#         two_words_connector: &quot; y &quot;
#         last_word_connector: &quot; o al menos &quot;

[&#39;uno&#39;, &#39;dos&#39;].to_sentence(locale: :es)
# =&gt; &quot;uno y dos&quot;

[&#39;uno&#39;, &#39;dos&#39;, &#39;tres&#39;].to_sentence(locale: :es)
# =&gt; &quot;uno o dos o al menos tres&quot;
</code></pre>
            </div>
          

            <details class="method__source">
              <summary>
                <span class="label">📝 Source code</span>
              </summary>

              <pre><code class="ruby"># File activesupport/lib/active_support/core_ext/array/conversions.rb, line 60
  def to_sentence(options = {})
    options.assert_valid_keys(:words_connector, :two_words_connector, :last_word_connector, :locale)

    default_connectors = {
      words_connector: &quot;, &quot;,
      two_words_connector: &quot; and &quot;,
      last_word_connector: &quot;, and &quot;
    }
    if options[:locale] != false &amp;&amp; defined?(I18n)
      i18n_connectors = I18n.translate(:&#39;support.array&#39;, locale: options[:locale], default: {})
      default_connectors.merge!(i18n_connectors)
    end
    options = default_connectors.merge!(options)

    case length
    when 0
      +&quot;&quot;
    when 1
      +&quot;#{self[0]}&quot;
    when 2
      +&quot;#{self[0]}#{options[:two_words_connector]}#{self[1]}&quot;
    else
      +&quot;#{self[0...-1].join(options[:words_connector])}#{options[:last_word_connector]}#{self[-1]}&quot;
    end
  end</code></pre>
              
                <a href="https://github.com/rails/rails/blob/dd8f7185faeca6ee968a6e9367f6d8601a83b8db/activesupport/lib/active_support/core_ext/array/conversions.rb#L60" target="_blank" class="github_url">🔎 See on GitHub</a>
              
            </details>
          
        </div>
        
        <div class="method">
          <h3 id="method-i-to_xml">
            
              to_xml(options = {})
            
          </h3>

          
            <div class="description">
              <p>Returns a string that represents the array in XML by invoking <code>to_xml</code> on each element. Active Record collections delegate their representation in XML to this method.</p>

<p>All elements are expected to respond to <code>to_xml</code>, if any of them does not then an exception is raised.</p>

<p>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:</p>

<pre><code>customer.projects.to_xml

&lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot;?&gt;
&lt;projects type=&quot;array&quot;&gt;
  &lt;project&gt;
    &lt;amount type=&quot;decimal&quot;&gt;20000.0&lt;/amount&gt;
    &lt;customer-id type=&quot;integer&quot;&gt;1567&lt;/customer-id&gt;
    &lt;deal-date type=&quot;date&quot;&gt;2008-04-09&lt;/deal-date&gt;
    ...
  &lt;/project&gt;
  &lt;project&gt;
    &lt;amount type=&quot;decimal&quot;&gt;57230.0&lt;/amount&gt;
    &lt;customer-id type=&quot;integer&quot;&gt;1567&lt;/customer-id&gt;
    &lt;deal-date type=&quot;date&quot;&gt;2008-04-15&lt;/deal-date&gt;
    ...
  &lt;/project&gt;
&lt;/projects&gt;
</code></pre>

<p>Otherwise the root element is “objects”:</p>

<pre><code>[{ foo: 1, bar: 2}, { baz: 3}].to_xml

&lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot;?&gt;
&lt;objects type=&quot;array&quot;&gt;
  &lt;object&gt;
    &lt;bar type=&quot;integer&quot;&gt;2&lt;/bar&gt;
    &lt;foo type=&quot;integer&quot;&gt;1&lt;/foo&gt;
  &lt;/object&gt;
  &lt;object&gt;
    &lt;baz type=&quot;integer&quot;&gt;3&lt;/baz&gt;
  &lt;/object&gt;
&lt;/objects&gt;
</code></pre>

<p>If the collection is empty the root element is “nil-classes” by default:</p>

<pre><code>[].to_xml

&lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot;?&gt;
&lt;nil-classes type=&quot;array&quot;/&gt;
</code></pre>

<p>To ensure a meaningful root element use the <code>:root</code> option:</p>

<pre><code>customer_with_no_projects.projects.to_xml(root: &#39;projects&#39;)

&lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot;?&gt;
&lt;projects type=&quot;array&quot;/&gt;
</code></pre>

<p>By default name of the node for the children of root is <code>root.singularize</code>. You can change it with the <code>:children</code> option.</p>

<p>The <code>options</code> hash is passed downwards:</p>

<pre><code>Message.all.to_xml(skip_types: true)

&lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot;?&gt;
&lt;messages&gt;
  &lt;message&gt;
    &lt;created-at&gt;2008-03-07T09:58:18+01:00&lt;/created-at&gt;
    &lt;id&gt;1&lt;/id&gt;
    &lt;name&gt;1&lt;/name&gt;
    &lt;updated-at&gt;2008-03-07T09:58:18+01:00&lt;/updated-at&gt;
    &lt;user-id&gt;1&lt;/user-id&gt;
  &lt;/message&gt;
&lt;/messages&gt;
</code></pre>
            </div>
          

            <details class="method__source">
              <summary>
                <span class="label">📝 Source code</span>
              </summary>

              <pre><code class="ruby"># File activesupport/lib/active_support/core_ext/array/conversions.rb, line 183
  def to_xml(options = {})
    require &quot;active_support/builder&quot; unless defined?(Builder::XmlMarkup)

    options = options.dup
    options[:indent]  ||= 2
    options[:builder] ||= Builder::XmlMarkup.new(indent: options[:indent])
    options[:root]    ||= \
      if first.class != Hash &amp;&amp; all?(first.class)
        underscored = ActiveSupport::Inflector.underscore(first.class.name)
        ActiveSupport::Inflector.pluralize(underscored).tr(&quot;/&quot;, &quot;_&quot;)
      else
        &quot;objects&quot;
      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: &quot;array&quot; }

    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</code></pre>
              
                <a href="https://github.com/rails/rails/blob/dd8f7185faeca6ee968a6e9367f6d8601a83b8db/activesupport/lib/active_support/core_ext/array/conversions.rb#L183" target="_blank" class="github_url">🔎 See on GitHub</a>
              
            </details>
          
        </div>
        
        <div class="method">
          <h3 id="method-i-without">
            
              without(*elements)
            
          </h3>

          
            <div class="description">
              
            </div>
          

            <div class="aka">
              Alias for: <a href="Array.html#method-i-excluding">excluding</a>
            </div>
          

        </div>
        
      
</div>

    </div>
</div>