Results for: "Dir.chdir"

With no argument, returns the value of $!, which is the result of the most recent pattern match (see Regexp global variables):

/c(.)t/ =~ 'cat'  # => 0
Regexp.last_match # => #<MatchData "cat" 1:"a">
/a/ =~ 'foo'      # => nil
Regexp.last_match # => nil

With non-negative integer argument n, returns the _n_th field in the matchdata, if any, or nil if none:

/c(.)t/ =~ 'cat'     # => 0
Regexp.last_match(0) # => "cat"
Regexp.last_match(1) # => "a"
Regexp.last_match(2) # => nil

With negative integer argument n, counts backwards from the last field:

Regexp.last_match(-1)       # => "a"

With string or symbol argument name, returns the string value for the named capture, if any:

/(?<lhs>\w+)\s*=\s*(?<rhs>\w+)/ =~ 'var = val'
Regexp.last_match        # => #<MatchData "var = val" lhs:"var"rhs:"val">
Regexp.last_match(:lhs)  # => "var"
Regexp.last_match('rhs') # => "val"
Regexp.last_match('foo') # Raises IndexError.

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

Iterates over each component of the path.

Pathname.new("/usr/bin/ruby").each_filename {|filename| ... }
  # yields "usr", "bin", and "ruby".

Returns an Enumerator if no block was given.

enum = Pathname.new("/usr/bin/ruby").each_filename
  # ... do stuff ...
enum.each { |e| ... }
  # yields "usr", "bin", and "ruby".

Iterates over each line in the file and yields a String object for each.

Iterates over the entries (files and subdirectories) in the directory, yielding a Pathname object for each entry.

Calls the block with each remaining line read from the stream; does nothing if already at end-of-file; returns self. See Line IO.

With a block given, calls the block with each remaining byte in the stream; see Byte IO.

With no block given, returns an enumerator.

With a block given, calls the block with each remaining codepoint in the stream; see Codepoint IO.

With no block given, returns an enumerator.

This returns the value that scan_until would return, without advancing the scan pointer. The match register is affected, though.

s = StringScanner.new("Fri Dec 12 1975 14:39")
s.check_until /12/          # -> "Fri Dec 12"
s.pos                       # -> 0
s.matched                   # -> 12

Mnemonic: it “checks” to see whether a scan_until will return a value.

Scans the string until the pattern is matched. Advances the scan pointer if advance_pointer_p, otherwise not. Returns the matched string if return_string_p is true, otherwise returns the number of bytes advanced. This method does affect the match register.

Returns the size of the most recent match in bytes, or nil if there was no recent match. This is different than matched.size, which will return the size in characters.

s = StringScanner.new('test string')
s.check /\w+/           # -> "test"
s.matched_size          # -> 4
s.check /\d+/           # -> nil
s.matched_size          # -> nil

Returns the pre-match

s = StringScanner.new('test string')
s.scan(/\w+/)           # -> "test"
s.scan(/\s+/)           # -> " "
s.pre_match             # -> "test"
s.post_match            # -> "string"

Returns the post-match

s = StringScanner.new('test string')
s.scan(/\w+/)           # -> "test"
s.scan(/\s+/)           # -> " "
s.pre_match             # -> "test"
s.post_match            # -> "string"

Whether scanner uses fixed anchor mode or not.

If fixed anchor mode is used, \A always matches the beginning of the string. Otherwise, \A always matches the current position.

Calls the given block with each value; returns self:

h = {foo: 0, bar: 1, baz: 2}
h.each_value {|value| puts value } # => {:foo=>0, :bar=>1, :baz=>2}

Output:

0
1
2

Returns a new Enumerator if no block given:

h = {foo: 0, bar: 1, baz: 2}
e = h.each_value # => #<Enumerator: {:foo=>0, :bar=>1, :baz=>2}:each_value>
h1 = e.each {|value| puts value }
h1 # => {:foo=>0, :bar=>1, :baz=>2}

Output:

0
1
2

Calls the given block with each key; returns self:

h = {foo: 0, bar: 1, baz: 2}
h.each_key {|key| puts key }  # => {:foo=>0, :bar=>1, :baz=>2}

Output:

foo
bar
baz

Returns a new Enumerator if no block given:

h = {foo: 0, bar: 1, baz: 2}
e = h.each_key # => #<Enumerator: {:foo=>0, :bar=>1, :baz=>2}:each_key>
h1 = e.each {|key| puts key }
h1 # => {:foo=>0, :bar=>1, :baz=>2}

Output:

foo
bar
baz

Returns a new Array containing the values associated with the given keys *keys:

h = {foo: 0, bar: 1, baz: 2}
h.fetch_values(:baz, :foo) # => [2, 0]

Returns a new empty Array if no arguments given.

When a block is given, calls the block with each missing key, treating the block’s return value as the value for that key:

h = {foo: 0, bar: 1, baz: 2}
values = h.fetch_values(:bar, :foo, :bad, :bam) {|key| key.to_s}
values # => [1, 0, "bad", "bam"]

When no block is given, raises an exception if any given key is not found.

Yields each environment variable name:

ENV.replace('foo' => '0', 'bar' => '1') # => ENV
names = []
ENV.each_key { |name| names.push(name) } # => ENV
names # => ["bar", "foo"]

Returns an Enumerator if no block given:

e = ENV.each_key # => #<Enumerator: {"bar"=>"1", "foo"=>"0"}:each_key>
names = []
e.each { |name| names.push(name) } # => ENV
names # => ["bar", "foo"]

Yields each environment variable value:

ENV.replace('foo' => '0', 'bar' => '1') # => ENV
values = []
ENV.each_value { |value| values.push(value) } # => ENV
values # => ["1", "0"]

Returns an Enumerator if no block given:

e = ENV.each_value # => #<Enumerator: {"bar"=>"1", "foo"=>"0"}:each_value>
values = []
e.each { |value| values.push(value) } # => ENV
values # => ["1", "0"]

Returns an enumerator which iterates over each line (separated by sep, which defaults to your platform’s newline character) of each file in ARGV. If a block is supplied, each line in turn will be yielded to the block, otherwise an enumerator is returned. The optional limit argument is an Integer specifying the maximum length of each line; longer lines will be split according to this limit.

This method allows you to treat the files supplied on the command line as a single file consisting of the concatenation of each named file. After the last line of the first file has been returned, the first line of the second file is returned. The ARGF.filename and ARGF.lineno methods can be used to determine the filename of the current line and line number of the whole input, respectively.

For example, the following code prints out each line of each named file prefixed with its line number, displaying the filename once per file:

ARGF.each_line do |line|
  puts ARGF.filename if ARGF.file.lineno == 1
  puts "#{ARGF.file.lineno}: #{line}"
end

While the following code prints only the first file’s name at first, and the contents with line number counted through all named files.

ARGF.each_line do |line|
  puts ARGF.filename if ARGF.lineno == 1
  puts "#{ARGF.lineno}: #{line}"
end

Iterates over each byte of each file in ARGV. A byte is returned as an Integer in the range 0..255.

This method allows you to treat the files supplied on the command line as a single file consisting of the concatenation of each named file. After the last byte of the first file has been returned, the first byte of the second file is returned. The ARGF.filename method can be used to determine the filename of the current byte.

If no block is given, an enumerator is returned instead.

For example:

ARGF.bytes.to_a  #=> [35, 32, ... 95, 10]

Iterates over each codepoint of each file in ARGF.

This method allows you to treat the files supplied on the command line as a single file consisting of the concatenation of each named file. After the last codepoint of the first file has been returned, the first codepoint of the second file is returned. The ARGF.filename method can be used to determine the name of the file in which the current codepoint appears.

If no block is given, an enumerator is returned instead.

Creates an option from the given parameters params. See Parameters for New Options.

The block, if given, is the handler for the created option. When the option is encountered during command-line parsing, the block is called with the argument given for the option, if any. See Option Handlers.

Returns the length (in characters) of the matched substring corresponding to the given argument.

When non-negative argument n is given, returns the length of the matched substring for the nth match:

m = /(.)(.)(\d+)(\d)(\w)?/.match("THX1138.")
# => #<MatchData "HX1138" 1:"H" 2:"X" 3:"113" 4:"8" 5:nil>
m.match_length(0) # => 6
m.match_length(4) # => 1
m.match_length(5) # => nil

When string or symbol argument name is given, returns the length of the matched substring for the named match:

m = /(?<foo>.)(.)(?<bar>.+)/.match("hoge")
# => #<MatchData "hoge" foo:"h" bar:"ge">
m.match_length('foo') # => 1
m.match_length(:bar)  # => 2