Returns an IO object representing the current file. This will be a File object unless the current file is a stream such as STDIN.
For example:
ARGF.to_io #=> #<File:glark.txt> ARGF.to_io #=> #<IO:<STDIN>>
Iterates over each character 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 character of the first file has been returned, the first character of the second file is returned. The ARGF.filename method can be used to determine the name of the file in which the current character appears.
If no block is given, an enumerator is returned instead.
Reads at most maxlen bytes from the ARGF stream in non-blocking mode.
Returns the file extension appended to the names of modified files under in-place edit mode. This value can be set using ARGF.inplace_mode= or passing the -i switch to the Ruby binary.
Sets the filename extension for in-place editing mode to the given String. Each file being edited has this value appended to its filename. The modified file is saved under this new name.
For example:
$ ruby argf.rb file.txt
ARGF.inplace_mode = '.bak'
ARGF.each_line do |line|
print line.sub("foo","bar")
end
Each line of file.txt has the first occurrence of “foo” replaced with “bar”, then the new line is written out to file.txt.bak.
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.
If single argument is specified, strings read from ARGF are tagged with the encoding specified.
If two encoding names separated by a colon are given, e.g. “ascii:utf-8”, the read string is converted from the first encoding (external encoding) to the second encoding (internal encoding), then tagged with the second encoding.
If two arguments are specified, they must be encoding objects or encoding names. Again, the first specifies the external encoding; the second specifies the internal encoding.
If the external encoding and the internal encoding are specified, the optional Hash argument can be used to adjust the conversion process. The structure of this hash is explained in the String#encode documentation.
For example:
ARGF.set_encoding('ascii') # Tag the input as US-ASCII text ARGF.set_encoding(Encoding::UTF_8) # Tag the input as UTF-8 text ARGF.set_encoding('utf-8','ascii') # Transcode the input from US-ASCII # to UTF-8.
Returns the String created by generating CSV from ary using the specified options.
Argument ary must be an Array.
Special options:
Option :row_sep defaults to "\n"> on Ruby 3.0 or later and <tt>$INPUT_RECORD_SEPARATOR ($/) otherwise.:
$INPUT_RECORD_SEPARATOR # => "\n"
This method accepts an additional option, :encoding, which sets the base Encoding for the output. This method will try to guess your Encoding from the first non-nil field in row, if possible, but you may need to use this parameter as a backup plan.
For other options, see Options for Generating.
Returns the String generated from an Array:
CSV.generate_line(['foo', '0']) # => "foo,0\n"
Raises an exception if ary is not an Array:
# Raises NoMethodError (undefined method `find' for :foo:Symbol) CSV.generate_line(:foo)
Returns the String created by generating CSV from using the specified options.
Argument rows must be an Array of row. Row is Array of String or CSV::Row.
Special options:
Option :row_sep defaults to "\n" on Ruby 3.0 or later and $INPUT_RECORD_SEPARATOR ($/) otherwise.:
$INPUT_RECORD_SEPARATOR # => "\n"
This method accepts an additional option, :encoding, which sets the base Encoding for the output. This method will try to guess your Encoding from the first non-nil field in row, if possible, but you may need to use this parameter as a backup plan.
For other options, see Options for Generating.
Returns the String generated from an
CSV.generate_lines(['foo', '0'], ['bar', '1'], ['baz', '2']) # => "foo,0\nbar,1\nbaz.2\n"
Raises an exception
# Raises NoMethodError (undefined method `find' for :foo:Symbol) CSV.generate_lines(:foo)
Returns the encoded column separator; used for parsing and writing; see {Option col_sep}:
CSV.new('').col_sep # => ","
Returns the encoded row separator; used for parsing and writing; see {Option row_sep}:
CSV.new('').row_sep # => "\n"
Returns the encoded quote character; used for parsing and writing; see {Option quote_char}:
CSV.new('').quote_char # => "\""
Returns true if the next row to be read is a header row; false otherwise.
Without headers:
string = "foo,0\nbar,1\nbaz,2\n" csv = CSV.new(string) csv.header_row? # => false
With headers:
string = "Name,Value\nfoo,0\nbar,1\nbaz,2\n" csv = CSV.new(string, headers: true) csv.header_row? # => true csv.shift # => #<CSV::Row "Name":"foo" "Value":"0"> csv.header_row? # => false
Raises an exception if the source is not opened for reading:
string = "foo,0\nbar,1\nbaz,2\n" csv = CSV.new(string) csv.close # Raises IOError (not opened for reading) csv.header_row?
Creates a new compiler for ERB. See ERB::Compiler.new for details
Returns a new binding each time near TOPLEVEL_BINDING for runs that do not specify a binding.
Return the appropriate error message in POSIX-defined format. If no error has occurred, returns nil.
Returns true if the ipaddr is an IPv4-compatible IPv6 address.
Returns a new ipaddr built by converting the native IPv4 address into an IPv4-compatible IPv6 address.
Returns the IPv6 zone identifier, if present. Raises InvalidAddressError if not an IPv6 address.
Returns the IPv6 zone identifier, if present. Raises InvalidAddressError if not an IPv6 address.
Returns the names of the binding’s local variables as symbols.
def foo a = 1 2.times do |n| binding.local_variables #=> [:a, :n] end end
This method is the short version of the following code:
binding.eval("local_variables")