Returns the result of interpreting ary as an array of [key, value] pairs.
[[:foo, :bar], [1, 2]].to_h # => {:foo => :bar, 1 => 2}
If a block is given, the results of the block on each element of the array will be used as pairs.
["foo", "bar"].to_h {|s| [s.ord, s]} # => {102=>"foo", 98=>"bar"}
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. See also Array#last for the opposite effect.
a = [ "q", "r", "s", "t" ] a.first #=> "q" a.first(2) #=> ["q", "r"]
Returns the last element(s) of self. If the array is empty, the first form returns nil.
See also Array#first for the opposite effect.
a = [ "w", "x", "y", "z" ] a.last #=> "z" a.last(2) #=> ["y", "z"]
Array Difference
Returns a new array that is a copy of the original array, removing all occurrences of any item that also appear in other_ary. The order is preserved from the original array.
It compares elements using their hash and eql? methods for efficiency.
[ 1, 1, 2, 2, 3, 3, 4, 5 ].difference([ 1, 2, 4 ]) #=> [ 3, 3, 5 ]
Note that while 1 and 2 were only present once in the array argument, and were present twice in the receiver array, all occurrences of each Integer are removed in the returned array.
Multiple array arguments can be supplied and all occurrences of any element in those supplied arrays that match the receiver will be removed from the returned array.
[ 1, 'c', :s, 'yep' ].difference([ 1 ], [ 'a', 'c' ]) #=> [ :s, "yep" ]
If you need set-like behavior, see the library class Set.
See also Array#-.
Returns a new array containing self‘s elements in reverse order.
[ "a", "b", "c" ].reverse #=> ["c", "b", "a"] [ 1 ].reverse #=> [1]
Reverses self in place.
a = [ "a", "b", "c" ] a.reverse! #=> ["c", "b", "a"] a #=> ["c", "b", "a"]
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 must implement a comparison between a and b and return an integer less than 0 when b follows a, 0 when a and b are equivalent, or an integer greater than 0 when a follows b.
The result is not guaranteed to be stable. When the comparison of two elements returns 0, the order of the elements is unpredictable.
ary = [ "d", "a", "e", "c", "b" ] ary.sort #=> ["a", "b", "c", "d", "e"] ary.sort {|a, b| b <=> a} #=> ["e", "d", "c", "b", "a"]
To produce the reverse order, the following can also be used (and may be faster):
ary.sort.reverse! #=> ["e", "d", "c", "b", "a"]
See also Enumerable#sort_by.
Sorts self in place.
Comparisons for the sort will be done using the <=> operator or using an optional code block.
The block must implement a comparison between a and b and return an integer less than 0 when b follows a, 0 when a and b are equivalent, or an integer greater than 0 when a follows b.
The result is not guaranteed to be stable. When the comparison of two elements returns 0, the order of the elements is unpredictable.
ary = [ "d", "a", "e", "c", "b" ] ary.sort! #=> ["a", "b", "c", "d", "e"] ary.sort! {|a, b| b <=> a} #=> ["e", "d", "c", "b", "a"]
See also Enumerable#sort_by.
Returns a new array containing the items in self for which the given block is not true. The ordering of non-rejected elements is maintained.
See also Array#delete_if
If no block is given, an Enumerator is returned instead.
Deletes every element of self for which the block evaluates to true, if no changes were made returns nil.
The array may not be changed instantly every time the block is called.
See also Enumerable#reject and Array#delete_if.
If no block is given, an Enumerator is returned instead.
Replaces the contents of self with the contents of other_ary, truncating or expanding if necessary.
a = [ "a", "b", "c", "d", "e" ] a.replace([ "x", "y", "z" ]) #=> ["x", "y", "z"] a #=> ["x", "y", "z"]
Creates a string representation of self, by calling inspect on each element.
[ "a", "b", "c" ].to_s #=> "[\"a\", \"b\", \"c\"]"
Prepends objects to the front of self, moving other elements upwards. See also Array#shift for the opposite effect.
a = [ "b", "c", "d" ] a.unshift("a") #=> ["a", "b", "c", "d"] a.unshift(1, 2) #=> [ 1, 2, "a", "b", "c", "d"]
Calculates the set of unambiguous abbreviations for the strings in self.
require 'abbrev' %w{ car cone }.abbrev #=> {"car"=>"car", "ca"=>"car", "cone"=>"cone", "con"=>"cone", "co"=>"cone"}
The optional pattern parameter is a pattern or a string. Only input strings that match the pattern or start with the string are included in the output hash.
%w{ fast boat day }.abbrev(/^.a/) #=> {"fast"=>"fast", "fas"=>"fast", "fa"=>"fast", "day"=>"day", "da"=>"day"} Abbrev.abbrev(%w{car box cone}, "ca") #=> {"car"=>"car", "ca"=>"car"}
See also Abbrev.abbrev
Returns a Hash containing implementation-dependent counters inside the VM.
This hash includes information about method/constant cache serials:
{
:global_method_state=>251,
:global_constant_state=>481,
:class_serial=>9029
}
The contents of the hash are implementation specific and may be changed in the future.
This method is only expected to work on C Ruby.
Returns a Digest subclass by name in a thread-safe manner even when on-demand loading is involved.
require 'digest' Digest("MD5") # => Digest::MD5 Digest(:SHA256) # => Digest::SHA256 Digest(:Foo) # => LoadError: library not found for class Digest::Foo -- digest/foo
cgi_runner.rb – CGI launcher.
Author: IPR – Internet Programming with Ruby – writers Copyright © 2000 TAKAHASHI Masayoshi, GOTOU YUUZOU Copyright © 2002 Internet Programming with Ruby writers. All rights reserved.
$IPR: cgi_runner.rb,v 1.9 2002/09/25 11:33:15 gotoyuzo Exp $
Returns object. This method is deprecated and will be removed in Ruby 3.2.
Returns false. This method is deprecated and will be removed in Ruby 3.2.
Returns object. This method is deprecated and will be removed in Ruby 3.2.
Prevents further modifications to obj. A RuntimeError will be raised if modification is attempted. There is no way to unfreeze a frozen object. See also Object#frozen?.
This method returns self.
a = [ "a", "b", "c" ] a.freeze a << "z"
produces:
prog.rb:3:in `<<': can't modify frozen Array (FrozenError) from prog.rb:3
Objects of the following classes are always frozen: Integer, Float, Symbol.
Returns a string representing obj. The default to_s prints the object’s class and an encoding of the object id. As a special case, the top-level object that is the initial execution context of Ruby programs returns “main”.
Returns the value of int as a BigDecimal.
require 'bigdecimal' require 'bigdecimal/util' 42.to_d # => 0.42e2
See also BigDecimal::new.
Returns a string containing the place-value representation of int with radix base (between 2 and 36).
12345.to_s #=> "12345" 12345.to_s(2) #=> "11000000111001" 12345.to_s(8) #=> "30071" 12345.to_s(10) #=> "12345" 12345.to_s(16) #=> "3039" 12345.to_s(36) #=> "9ix" 78546939656932.to_s(36) #=> "rubyrules"