Returns true if there is an environment variable with the given name:
ENV.replace('foo' => '0', 'bar' => '1') ENV.include?('foo') # => true
Returns false if name is a valid String and there is no such environment variable:
ENV.include?('baz') # => false
Returns false if name is the empty String or is a String containing character '=':
ENV.include?('') # => false ENV.include?('=') # => false
Raises an exception if name is a String containing the NUL character "\0":
ENV.include?("\0") # Raises ArgumentError (bad environment variable name: contains null byte)
Raises an exception if name has an encoding that is not ASCII-compatible:
ENV.include?("\xa1\xa1".force_encoding(Encoding::UTF_16LE)) # Raises ArgumentError (bad environment variable name: ASCII incompatible encoding: UTF-16LE)
Raises an exception if name is not a String:
ENV.include?(Object.new) # TypeError (no implicit conversion of Object into String)
Reads length bytes from ARGF. The files named on the command line are concatenated and treated as a single file by this method, so when called without arguments the contents of this pseudo file are returned in their entirety.
length must be a non-negative integer or nil.
If length is a positive integer, read tries to read length bytes without any conversion (binary mode). It returns nil if an EOF is encountered before anything can be read. Fewer than length bytes are returned if an EOF is encountered during the read. In the case of an integer length, the resulting string is always in ASCII-8BIT encoding.
If length is omitted or is nil, it reads until EOF and the encoding conversion is applied, if applicable. A string is returned even if EOF is encountered before any data is read.
If length is zero, it returns an empty string ("").
If the optional outbuf argument is present, it must reference a String, which will receive the data. The outbuf will contain only the received data after the method call even if it is not empty at the beginning.
For example:
$ echo "small" > small.txt $ echo "large" > large.txt $ ./glark.rb small.txt large.txt ARGF.read #=> "small\nlarge" ARGF.read(200) #=> "small\nlarge" ARGF.read(2) #=> "sm" ARGF.read(0) #=> ""
Note that this method behaves like the fread() function in C. This means it retries to invoke read(2) system calls to read data with the specified length. If you need the behavior like a single read(2) system call, consider ARGF#readpartial or ARGF#read_nonblock.
Reads at most maxlen bytes from the ARGF stream.
If the optional outbuf argument is present, it must reference a String, which will receive the data. The outbuf will contain only the received data after the method call even if it is not empty at the beginning.
It raises EOFError on end of ARGF stream. Since ARGF stream is a concatenation of multiple files, internally EOF is occur for each file. ARGF.readpartial returns empty strings for EOFs except the last one and raises EOFError for the last one.
Reads each file in ARGF in its entirety, returning an Array containing lines from the files. Lines are assumed to be separated by sep.
lines = ARGF.readlines lines[0] #=> "This is line one\n"
See IO.readlines for a full description of all options.
Returns the next line from the current file in ARGF.
By default lines are assumed to be separated by $/; to use a different character as a separator, supply it as a String for the sep argument.
The optional limit argument specifies how many characters of each line to return. By default all characters are returned.
An EOFError is raised at the end of the file.
Reads the next character from ARGF and returns it as a String. Raises an EOFError after the last character of the last file has been read.
For example:
$ echo "foo" > file $ ruby argf.rb file ARGF.readchar #=> "f" ARGF.readchar #=> "o" ARGF.readchar #=> "o" ARGF.readchar #=> "\n" ARGF.readchar #=> end of file reached (EOFError)
Reads the next 8-bit byte from ARGF and returns it as an Integer. Raises an EOFError after the last byte of the last file has been read.
For example:
$ echo "foo" > file $ ruby argf.rb file ARGF.readbyte #=> 102 ARGF.readbyte #=> 111 ARGF.readbyte #=> 111 ARGF.readbyte #=> 10 ARGF.readbyte #=> end of file reached (EOFError)
Positions the current file to the beginning of input, resetting ARGF.lineno to zero.
ARGF.readline #=> "This is line one\n" ARGF.rewind #=> 0 ARGF.lineno #=> 0 ARGF.readline #=> "This is line one\n"
Puts ARGF into binary mode. Once a stream is in binary mode, it cannot be reset to non-binary mode. This option has the following effects:
Newline conversion is disabled.
Encoding conversion is disabled.
Content is treated as ASCII-8BIT.
Returns true if ARGF is being read in binary mode; false otherwise. To enable binary mode use ARGF.binmode.
For example:
ARGF.binmode? #=> false ARGF.binmode ARGF.binmode? #=> true
:method: freeze Freeze both the object returned by _getobj_ and self.
Executes the generated ERB code to produce a completed template, returning the results of that code.
b accepts a Binding object which is used to set the context of code evaluation.
Returns a new ipaddr built by converting the IPv6 address into a native IPv4 address. If the IP address is not an IPv4-mapped or IPv4-compatible IPv6 address, returns self.
Returns the prefix length in bits for the ipaddr.
Sets the prefix length in bits
Directs to reject specified class argument.
type
Argument class specifier, any object including Class.
reject(type)
Release code
Returns version string from program_name, version and release.
Returns an array of member names of the data class:
Measure = Data.define(:amount, :unit) Measure.members # => [:amount, :unit]
Returns the member names from self as an array:
Measure = Data.define(:amount, :unit) distance = Measure[10, 'km'] distance.members #=> [:amount, :unit]
Returns the regexp that produced the match:
m = /a.*b/.match("abc") # => #<MatchData "ab"> m.regexp # => /a.*b/
Returns the array of captures, which are all matches except m[0]:
m = /(.)(.)(\d+)(\d)/.match("THX1138.") # => #<MatchData "HX1138" 1:"H" 2:"X" 3:"113" 4:"8"> m[0] # => "HX1138" m.captures # => ["H", "X", "113", "8"]
Related: MatchData.to_a.
This says “you can break a line here if necessary”, and a width-column text sep is inserted if a line is not broken at the point.
If sep is not specified, “ ” is used.
If width is not specified, sep.length is used. You will have to specify this when sep is a multibyte character, for example.
Looks up the first IP address for name.