Reads a one-character string from ios. Raises an EOFError on end of file.
f = File.new("testfile") f.readchar #=> "h" f.readchar #=> "e"
Reads a byte as with IO#getbyte, 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.
Returns true if the underlying file descriptor of ios will be closed automatically at its finalization, otherwise false.
Sets auto-close flag.
f = open("/dev/null") IO.for_fd(f.fileno) # ... f.gets # may cause Errno::EBADF f = open("/dev/null") IO.for_fd(f.fileno).autoclose = false # ... f.gets # won't cause Errno::EBADF
Returns an integer representing the numeric file descriptor for ios.
$stdin.fileno #=> 0 $stdout.fileno #=> 1
Deletes every key-value pair from gdbm for which block evaluates to true.
Returns a hash copy of gdbm where all key-value pairs from gdbm for which block evaluates to true are removed. See also: delete_if
Replaces the content of gdbm with the key-value pairs of other. other must have an each_pair method.
Turns the database’s fast mode on or off. If fast mode is turned on, gdbm does not wait for writes to be flushed to the disk before continuing.
This option is obsolete for gdbm >= 1.8 since fast mode is turned on by default. See also: syncmode=
Returns an array of all key-value pairs contained in the database.
Converts the OpenStruct to a hash with keys representing each attribute (as symbols) and their corresponding values.
If a block is given, the results of the block on each pair of the receiver will be used as pairs.
require "ostruct" data = OpenStruct.new("country" => "Australia", :capital => "Canberra") data.to_h # => {:country => "Australia", :capital => "Canberra" } data.to_h {|name, value| [name.to_s, value.upcase] } # => {"country" => "AUSTRALIA", "capital" => "CANBERRA" }
Iterates over the range, passing each nth element to the block. If begin and end are numeric, n is added for each iteration. Otherwise step invokes succ to iterate through range elements.
If no block is given, an enumerator is returned instead. Especially, the enumerator is an Enumerator::ArithmeticSequence if begin and end of the range are numeric.
range = Xs.new(1)..Xs.new(10) range.step(2) {|x| puts x} puts range.step(3) {|x| puts x}
produces:
1 x 3 xxx 5 xxxxx 7 xxxxxxx 9 xxxxxxxxx 1 x 4 xxxx 7 xxxxxxx 10 xxxxxxxxxx
See Range for the definition of class Xs.
Returns the first object in the range, or an array of the first n elements.
(10..20).first #=> 10 (10..20).first(3) #=> [10, 11, 12]
Returns the last object in the range, or an array of the last n elements.
Note that with no arguments last will return the object that defines the end of the range even if exclude_end? is true.
(10..20).last #=> 20 (10...20).last #=> 20 (10..20).last(3) #=> [18, 19, 20] (10...20).last(3) #=> [17, 18, 19]
Returns an array containing the items in the range.
(1..7).to_a #=> [1, 2, 3, 4, 5, 6, 7] (1..).to_a #=> RangeError: cannot convert endless range to an array
Convert this range object to a printable form (using to_s to convert the begin and end objects).
Returns a string containing the regular expression and its options (using the (?opts:source) notation. This string can be fed back in to Regexp::new to a regular expression with the same semantics as the original. (However, Regexp#== may not return true when comparing the two, as the source of the regular expression itself may differ, as the example shows). Regexp#inspect produces a generally more readable version of rxp.
r1 = /ab+c/ix #=> /ab+c/ix s1 = r1.to_s #=> "(?ix-m:ab+c)" r2 = Regexp.new(s1) #=> /(?ix-m:ab+c)/ r1 == r2 #=> false r1.source #=> "ab+c" r2.source #=> "(?ix-m:ab+c)"
Replaces the contents of the set with the contents of the given enumerable object and returns self.
set = Set[1, 'c', :s] #=> #<Set: {1, "c", :s}> set.replace([1, 2]) #=> #<Set: {1, 2}> set #=> #<Set: {1, 2}>
Converts the set to an array. The order of elements is uncertain.
Set[1, 2].to_a #=> [1, 2] Set[1, 'c', :s].to_a #=> [1, "c", :s]
Equivalent to Set#delete_if, but returns nil if no changes were made. Returns an enumerator if no block is given.
Resets the internal state after modification to existing elements and returns self.
Elements will be reindexed and deduplicated.