Returns a description of this struct as a string.
Tries to set console size. The effect depends on the platform and the running environment.
You must require ‘io/console’ to use this method.
Reads the entire file specified by name as individual lines, and returns those lines in an array. Lines are separated by sep.
a = IO.readlines("testfile") a[0] #=> "This is line one\n" b = IO.readlines("testfile", chomp: true) b[0] #=> "This is line one"
If the last argument is a hash, it’s the keyword argument to open.
The options hash accepts the following keys:
When the optional chomp keyword argument has a true value, \n, \r, and \r\n will be removed from the end of each line.
See also IO.read for details about open_args.
Opens the file, optionally seeks to the given offset, then returns length bytes (defaulting to the rest of the file). binread ensures the file is closed before returning. The open mode would be “rb:ASCII-8BIT”.
IO.binread("testfile") #=> "This is line one\nThis is line two\nThis is line three\nAnd so on...\n" IO.binread("testfile", 20) #=> "This is line one\nThi" IO.binread("testfile", 20, 10) #=> "ne one\nThis is line "
Same as IO.write except opening the file in binary mode and ASCII-8BIT encoding (“wb:ASCII-8BIT”).
Writes the given object(s) to ios. Returns nil.
The stream must be opened for writing. Each given object that isn’t a string will be converted by calling its to_s method. When called without arguments, prints the contents of $_.
If the output field separator ($,) is not nil, it is inserted between objects. If the output record separator ($\) is not nil, it is appended to the output.
$stdout.print("This is ", 100, " percent.\n")
produces:
This is 100 percent.
Formats and writes to ios, converting parameters under control of the format string. See Kernel#sprintf for details.
This is a deprecated alias for each_line.
This is a deprecated alias for each_codepoint.
Returns the current line number in ios. The stream must be opened for reading. lineno counts the number of times gets is called rather than the number of newlines encountered. The two values will differ if gets is called with a separator other than newline.
Methods that use $/ like each, lines and readline will also increment lineno.
See also the $. variable.
f = File.new("testfile") f.lineno #=> 0 f.gets #=> "This is line one\n" f.lineno #=> 1 f.gets #=> "This is line two\n" f.lineno #=> 2
Manually sets the current line number to the given value. $. is updated only on the next read.
f = File.new("testfile") f.gets #=> "This is line one\n" $. #=> 1 f.lineno = 1000 f.lineno #=> 1000 $. #=> 1 # lineno of last read f.gets #=> "This is line two\n" $. #=> 1001 # lineno of last read
Reads all of the lines in ios, and returns them in an array. Lines are separated by the optional sep. If sep is nil, the rest of the stream is returned as a single record. If the first argument is an integer, or an optional second argument is given, the returning string would not be longer than the given value in bytes. The stream must be opened for reading or an IOError will be raised.
f = File.new("testfile") f.readlines[0] #=> "This is line one\n" f = File.new("testfile", chomp: true) f.readlines[0] #=> "This is line one"
See IO.readlines for details about getline_args.
Reads a line as with IO#gets, but raises an EOFError on end of file.
Positions ios to the beginning of input, resetting lineno to zero.
f = File.new("testfile") f.readline #=> "This is line one\n" f.rewind #=> 0 f.lineno #=> 0 f.readline #=> "This is line one\n"
Note that it cannot be used with streams such as pipes, ttys, and sockets.
Return a string describing this IO object.
Returns a hash created by using gdbm’s values as keys, and the keys as values.
Returns true if the given key k exists within the database. Returns false otherwise.
Returns a string containing a detailed summary of the keys and values.
Convert this range object to a printable form (using inspect to convert the begin and end objects).
Returns true if obj is an element of the range, false otherwise. If begin and end are numeric, comparison is done according to the magnitude of the values.
("a".."z").include?("g") #=> true ("a".."z").include?("A") #=> false ("a".."z").include?("cc") #=> false
Returns a MatchData object describing the match, or nil if there was no match. This is equivalent to retrieving the value of the special variable $~ following a normal match. If the second parameter is present, it specifies the position in the string to begin the search.
/(.)(.)(.)/.match("abc")[2] #=> "b" /(.)(.)/.match("abc", 1)[2] #=> "c"
If a block is given, invoke the block with MatchData if match succeed, so that you can write
/M(.*)/.match("Matz") do |m| puts m[0] puts m[1] end
instead of
if m = /M(.*)/.match("Matz") puts m[0] puts m[1] end
The return value is a value from block execution in this case.
Returns a true or false indicates whether the regexp is matched or not without updating $~ and other related variables. If the second parameter is present, it specifies the position in the string to begin the search.
/R.../.match?("Ruby") #=> true /R.../.match?("Ruby", 1) #=> false /P.../.match?("Ruby") #=> false $& #=> nil
Produce a nicely formatted string-version of rxp. Perhaps surprisingly, #inspect actually produces the more natural version of the string than #to_s.
/ab+c/ix.inspect #=> "/ab+c/ix"