Returns true if rat is less than 0.
Returns the absolute value of rat.
(1/2r).abs #=> (1/2) (-1/2r).abs #=> (1/2)
Rational#magnitude is an alias for Rational#abs.
Returns rat truncated (toward zero) to a precision of ndigits decimal digits (default: 0).
When the precision is negative, the returned value is an integer with at least ndigits.abs trailing zeros.
Returns a rational when ndigits is positive, otherwise returns an integer.
Rational(3).truncate #=> 3 Rational(2, 3).truncate #=> 0 Rational(-3, 2).truncate #=> -1 # decimal - 1 2 3 . 4 5 6 # ^ ^ ^ ^ ^ ^ # precision -3 -2 -1 0 +1 +2 Rational('-123.456').truncate(+1).to_f #=> -123.4 Rational('-123.456').truncate(-1) #=> -120
Returns a simpler approximation of the value if the optional argument eps is given (rat-|eps| <= result <= rat+|eps|), self otherwise.
r = Rational(5033165, 16777216) r.rationalize #=> (5033165/16777216) r.rationalize(Rational('0.01')) #=> (3/10) r.rationalize(Rational('0.1')) #=> (1/3)
Returns a hash of parsed elements.
Raise an ArgumentError when the string length is longer than limit. You can stop this check by passing ‘limit: nil`, but note that it may take a long time to parse.
Creates a new Date object by parsing from a string according to some RFC 2616 format.
Date.httpdate('Sat, 03 Feb 2001 00:00:00 GMT') #=> #<Date: 2001-02-03 ...>
Raise an ArgumentError when the string length is longer than limit. You can stop this check by passing ‘limit: nil`, but note that it may take a long time to parse.
Returns true if the date is Saturday.
This method is equivalent to strftime(‘%a, %d %b %Y %T GMT’). See also RFC 2616.
Creates a new DateTime object by parsing from a string according to some RFC 2616 format.
DateTime.httpdate('Sat, 03 Feb 2001 04:05:06 GMT') #=> #<DateTime: 2001-02-03T04:05:06+00:00 ...>
Raise an ArgumentError when the string length is longer than limit. You can stop this check by passing ‘limit: nil`, but note that it may take a long time to parse.
Parses date as an HTTP-date defined by RFC 2616 and converts it to a Time object.
ArgumentError is raised if date is not compliant with RFC 2616 or if the Time class cannot represent specified date.
See httpdate for more information on this format.
require 'time' Time.httpdate("Thu, 06 Oct 2011 02:26:12 GMT") #=> 2011-10-06 02:26:12 UTC
You must require ‘time’ to use this method.
Returns a string which represents the time as RFC 1123 date of HTTP-date defined by RFC 2616:
day-of-week, DD month-name CCYY hh:mm:ss GMT
Note that the result is always UTC (GMT).
require 'time' t = Time.now t.httpdate # => "Thu, 06 Oct 2011 02:26:12 GMT"
You must require ‘time’ to use this method.
Returns a new Time object based the on given arguments; its timezone is UTC.
In the first form (up to seven arguments), argument year is required.
Time.utc(2000) # => 2000-01-01 00:00:00 UTC Time.utc(0, 1, 2, 3, 4, 5, 6.5) # => 0000-01-02 03:04:05.0000065 UTC
In the second form, all ten arguments are required, though the last four are ignored. This form is useful for creating a time from a 10-element array such as is returned by to_a.
array = Time.now.to_a p array # => [57, 26, 13, 24, 4, 2021, 6, 114, true, "Central Daylight Time"] array[5] = 2000 Time.utc(*array) # => 2000-04-24 13:26:57 UTC
Parameters:
year: an integer year.
month: a month value, which may be:
An integer month in the range 1..12.
A 3-character string that matches regular expression /jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec/i.
day: an integer day in the range 1..31 (less than 31 for some months).
hour: an integer hour in the range 0..23.
min: an integer minute in the range 0..59.
isec_i is the integer number of seconds in the range 0..60.
usec is the number of microseconds (Integer, Float, or Rational) in the range 0..1000000.
Alias: Time.gm.
Related: Time.local.
Converts time to UTC (GMT), modifying the receiver.
t = Time.now #=> 2007-11-19 08:18:31 -0600 t.gmt? #=> false t.gmtime #=> 2007-11-19 14:18:31 UTC t.gmt? #=> true t = Time.now #=> 2007-11-19 08:18:51 -0600 t.utc? #=> false t.utc #=> 2007-11-19 14:18:51 UTC t.utc? #=> true
Returns a new Time object representing time in UTC.
t = Time.local(2000,1,1,20,15,1) #=> 2000-01-01 20:15:01 -0600 t.gmt? #=> false y = t.getgm #=> 2000-01-02 02:15:01 UTC y.gmt? #=> true t == y #=> true
Returns true if time represents a time in UTC (GMT).
t = Time.now #=> 2007-11-19 08:15:23 -0600 t.utc? #=> false t = Time.gm(2000,"jan",1,20,15,1) #=> 2000-01-01 20:15:01 UTC t.utc? #=> true t = Time.now #=> 2007-11-19 08:16:03 -0600 t.gmt? #=> false t = Time.gm(2000,1,1,20,15,1) #=> 2000-01-01 20:15:01 UTC t.gmt? #=> true
Returns true if time represents Saturday.
t = Time.local(2006, 6, 10) #=> 2006-06-10 00:00:00 -0500 t.saturday? #=> true
Time
This form accepts a Time object time and optional keyword argument in:
Time.at(Time.new) # => 2021-04-26 08:52:31.6023486 -0500 Time.at(Time.new, in: '+09:00') # => 2021-04-26 22:52:31.6023486 +0900
Seconds
This form accepts a numeric number of seconds sec and optional keyword argument in:
Time.at(946702800) # => 1999-12-31 23:00:00 -0600 Time.at(946702800, in: '+09:00') # => 2000-01-01 14:00:00 +0900
Seconds with Subseconds and Units
This form accepts an integer number of seconds sec_i, a numeric number of milliseconds msec, a symbol argument for the subsecond unit type (defaulting to :usec), and an optional keyword argument in:
Time.at(946702800, 500, :millisecond) # => 1999-12-31 23:00:00.5 -0600 Time.at(946702800, 500, :millisecond, in: '+09:00') # => 2000-01-01 14:00:00.5 +0900 Time.at(946702800, 500000) # => 1999-12-31 23:00:00.5 -0600 Time.at(946702800, 500000, :usec) # => 1999-12-31 23:00:00.5 -0600 Time.at(946702800, 500000, :microsecond) # => 1999-12-31 23:00:00.5 -0600 Time.at(946702800, 500000, in: '+09:00') # => 2000-01-01 14:00:00.5 +0900 Time.at(946702800, 500000, :usec, in: '+09:00') # => 2000-01-01 14:00:00.5 +0900 Time.at(946702800, 500000, :microsecond, in: '+09:00') # => 2000-01-01 14:00:00.5 +0900 Time.at(946702800, 500000000, :nsec) # => 1999-12-31 23:00:00.5 -0600 Time.at(946702800, 500000000, :nanosecond) # => 1999-12-31 23:00:00.5 -0600 Time.at(946702800, 500000000, :nsec, in: '+09:00') # => 2000-01-01 14:00:00.5 +0900 Time.at(946702800, 500000000, :nanosecond, in: '+09:00') # => 2000-01-01 14:00:00.5 +0900
Parameters:
isec_i is the integer number of seconds in the range 0..60.
msec is the number of milliseconds (Integer, Float, or Rational) in the range 0..1000.
usec is the number of microseconds (Integer, Float, or Rational) in the range 0..1000000.
nsec is the number of nanoseconds (Integer, Float, or Rational) in the range 0..1000000000.
in: zone: a timezone zone, which may be:
A string offset from UTC.
A single letter offset from UTC, in the range 'A'..'Z', 'J' (the so-called military timezone) excluded.
An integer number of seconds.
A timezone object; see Timezone Argument for details.
Calls the given block with the value of each member; returns self:
Customer = Struct.new(:name, :address, :zip) joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345) joe.each {|value| p value }
Output:
"Joe Smith" "123 Maple, Anytown NC" 12345
Returns an Enumerator if no block is given.
Related: each_pair.
Returns pathname configuration variable using fpathconf().
name should be a constant under Etc which begins with PC_.
The return value is an integer or nil. nil means indefinite limit. (fpathconf() returns -1 but errno is not set.)
require 'etc' IO.pipe {|r, w| p w.pathconf(Etc::PC_PIPE_BUF) #=> 4096 }
Enables/disables echo back. On some platforms, all combinations of this flags and raw/cooked mode may not be valid.
You must require ‘io/console’ to use this method.
Yields self with disabling echo back.
STDIN.noecho(&:gets)
will read and return a line without echo back.
You must require ‘io/console’ to use this method.
Returns status information for ios as an object of type File::Stat.
f = File.new("testfile") s = f.stat "%o" % s.mode #=> "100644" s.blksize #=> 4096 s.atime #=> Wed Apr 09 08:53:54 CDT 2003
Executes the block for every line in the named I/O port, where lines are separated by sep.
If no block is given, an enumerator is returned instead.
If name starts with a pipe character ("|") and the receiver is the IO class, a subprocess is created in the same way as Kernel#open, and its output is returned. Consider to use File.foreach to disable the behavior of subprocess invocation.
File.foreach("testfile") {|x| print "GOT ", x } IO.foreach("| cat testfile") {|x| print "GOT ", x }
produces:
GOT This is line one GOT This is line two GOT This is line three GOT And so on...
If the last argument is a hash, it’s the keyword argument to open. See IO.readlines for details about getline_args. And see also IO.read for details about open_args.
If obj is Numeric, write the character whose code is the least-significant byte of obj. If obj is String, write the first character of obj to ios. Otherwise, raise TypeError.
$stdout.putc "A" $stdout.putc 65
produces:
AA