Returns the number of environment variables.
ENV.has_key?, ENV.member?, and ENV.key? are aliases for ENV.include?.
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)
This is a deprecated alias for each_line.
This is a deprecated alias for each_codepoint.
Reads ARGF‘s current file in its entirety, returning an Array of its lines, one line per element. Lines are assumed to be separated by sep.
lines = ARGF.readlines lines[0] #=> "This is line one\n"
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.
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
Writes string if inplace mode.
Returns the current line number of ARGF as a whole. This value can be set manually with ARGF.lineno=.
For example:
ARGF.lineno #=> 0 ARGF.readline #=> "This is line 1\n" ARGF.lineno #=> 1
Sets the line number of ARGF as a whole to the given Integer.
ARGF sets the line number automatically as you read data, so normally you will not need to set it explicitly. To access the current line number use ARGF.lineno.
For example:
ARGF.lineno #=> 0 ARGF.readline #=> "This is line 1\n" ARGF.lineno #=> 1 ARGF.lineno = 0 #=> 0 ARGF.lineno #=> 0
Returns “ARGF”.
Synonym for $stdout.
Alias for CSV::read().
The line number of the last row read from this file. Fields with nested line-end characters will not affect this count.
The last row read from this file.
Rewinds the underlying IO object and resets CSV’s lineno() counter.
Returns the IO used as stdout. Defaults to STDOUT