Returns the Encoding object that represents the encoding of the file. If the stream is write mode and no encoding is specified, returns nil.
Returns the Encoding of the internal string if conversion is specified. Otherwise returns nil.
Returns the size (in bytes) of the matched substring from the most recent match [match attempt] if it was successful, or nil otherwise; see [Basic Matched Values]:
scanner = StringScanner.new('foobarbaz') scanner.matched_size # => nil pos = 3 scanner.exist?(/baz/) # => 9 scanner.matched_size # => 3 scanner.exist?(/nope/) # => nil scanner.matched_size # => nil
Returns the substring that precedes the matched substring from the most recent match attempt if it was successful, or nil otherwise; see [Basic Match Values]:
scanner = StringScanner.new('foobarbaz') scanner.pre_match # => nil scanner.pos = 3 scanner.exist?(/baz/) # => 6 scanner.pre_match # => "foobar" # Substring of entire string, not just target string. scanner.exist?(/nope/) # => nil scanner.pre_match # => nil
Returns the substring that follows the matched substring from the most recent match attempt if it was successful, or nil otherwise; see [Basic Match Values]:
scanner = StringScanner.new('foobarbaz') scanner.post_match # => nil scanner.pos = 3 scanner.match?(/bar/) # => 3 scanner.post_match # => "baz" scanner.match?(/nope/) # => nil scanner.post_match # => nil
Returns an array of captured substrings, or nil of none.
For each specifier, the returned substring is [specifier]; see [].
scanner = StringScanner.new('Fri Dec 12 1975 14:39') pattern = /(?<wday>\w+) (?<month>\w+) (?<day>\d+) / scanner.match?(pattern) scanner.values_at(*0..3) # => ["Fri Dec 12 ", "Fri", "Dec", "12"] scanner.values_at(*%i[wday month day]) # => ["Fri", "Dec", "12"]
With a block given, calls the block with each key-value pair; returns self:
h = {foo: 0, bar: 1, baz: 2} h.each_pair {|key, value| puts "#{key}: #{value}"} # => {foo: 0, bar: 1, baz: 2}
Output:
foo: 0 bar: 1 baz: 2
With no block given, returns a new Enumerator.
Related: see Methods for Iterating.
Returns a new array containing values for the given keys:
h = {foo: 0, bar: 1, baz: 2} h.values_at(:baz, :foo) # => [2, 0]
The hash default is returned for each key that is not found:
h.values_at(:hello, :foo) # => [nil, 0]
Related: see Methods for Fetching.
Yields each environment variable name and its value as a 2-element Array:
h = {} ENV.each_pair { |name, value| h[name] = value } # => ENV h # => {"bar"=>"1", "foo"=>"0"}
Returns an Enumerator if no block given:
h = {} e = ENV.each_pair # => #<Enumerator: {"bar"=>"1", "foo"=>"0"}:each_pair> e.each { |name, value| h[name] = value } # => ENV h # => {"bar"=>"1", "foo"=>"0"}
Returns an Array containing the environment variable values associated with the given names:
ENV.replace('foo' => '0', 'bar' => '1', 'baz' => '2') ENV.values_at('foo', 'baz') # => ["0", "2"]
Returns nil in the Array for each name that is not an ENV name:
ENV.values_at('foo', 'bat', 'bar', 'bam') # => ["0", nil, "1", nil]
Returns an empty Array if no names given.
Raises an exception if any name is invalid. See Invalid Names and Values.
Returns the external encoding for files read from ARGF as an Encoding object. The external encoding is the encoding of the text as stored in a file. Contrast with ARGF.internal_encoding, which is the encoding used to represent this text within Ruby.
To set the external encoding use ARGF.set_encoding.
For example:
ARGF.external_encoding #=> #<Encoding:UTF-8>
Returns the internal encoding for strings read from ARGF as an Encoding object.
If ARGF.set_encoding has been called with two encoding names, the second is returned. Otherwise, if Encoding.default_external has been set, that value is returned. Failing that, if a default external encoding was specified on the command-line, that value is used. If the encoding is unknown, nil is returned.
Returns a string for DNS reverse lookup compatible with RFC3172.
Returns the usable width for out. As the width of out:
If out is assigned to a tty device, its width is used.
Otherwise, or it could not get the value, the COLUMN environment variable is assumed to be set to the width.
If COLUMN is not set to a non-zero number, 80 is assumed.
And finally, returns the above width value - 1.
This -1 is for Windows command prompt, which moves the cursor to the next line if it reaches the last column.
Returns match and captures at the given indexes, which may include any mixture of:
Integers.
Ranges.
Names (strings and symbols).
Examples:
m = /(.)(.)(\d+)(\d)/.match("THX1138: The Movie") # => #<MatchData "HX1138" 1:"H" 2:"X" 3:"113" 4:"8"> m.values_at(0, 2, -2) # => ["HX1138", "X", "113"] m.values_at(1..2, -1) # => ["H", "X", "8"] m = /(?<a>\d+) *(?<op>[+\-*\/]) *(?<b>\d+)/.match("1 + 2") # => #<MatchData "1 + 2" a:"1" op:"+" b:"2"> m.values_at(0, 1..2, :a, :b, :op) # => ["1 + 2", "1", "+", "1", "2", "+"]
Returns the substring of the target string from its beginning up to the first match in self (that is, self[0]); equivalent to regexp global variable $`:
m = /(.)(.)(\d+)(\d)/.match("THX1138.") # => #<MatchData "HX1138" 1:"H" 2:"X" 3:"113" 4:"8"> m[0] # => "HX1138" m.pre_match # => "T"
Related: MatchData#post_match.
Returns the substring of the target string from the end of the first match in self (that is, self[0]) to the end of the string; equivalent to regexp global variable $':
m = /(.)(.)(\d+)(\d)/.match("THX1138: The Movie") # => #<MatchData "HX1138" 1:"H" 2:"X" 3:"113" 4:"8"> m[0] # => "HX1138" m.post_match # => ": The Movie"\
Related: MatchData.pre_match.
This is similar to PrettyPrint::format but the result has no breaks.
maxwidth, newline and genspace are ignored.
The invocation of breakable in the block doesn’t break a line and is treated as just an invocation of text.
Returns the object for which the receiver is the singleton class.
Raises an TypeError if the class is not a singleton class.
class Foo; end Foo.singleton_class.attached_object #=> Foo Foo.attached_object #=> TypeError: `Foo' is not a singleton class Foo.new.singleton_class.attached_object #=> #<Foo:0x000000010491a370> TrueClass.attached_object #=> TypeError: `TrueClass' is not a singleton class NilClass.attached_object #=> TypeError: `NilClass' is not a singleton class
Returns the Ruby source filename and line number of the binding object.
Returns the location where the Proc was defined. The returned Array contains:
(1) the Ruby source filename (2) the line number where the definition starts (3) the column number where the definition starts (4) the line number where the definition ends (5) the column number where the definitions ends
This method will return nil if the Proc was not defined in Ruby (i.e. native).
Returns the location where the method was defined. The returned Array contains:
(1) the Ruby source filename (2) the line number where the definition starts (3) the column number where the definition starts (4) the line number where the definition ends (5) the column number where the definitions ends
This method will return nil if the method was not defined in Ruby (i.e. native).