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.
Creates a new Time object with the value given by time, the given number of seconds_with_frac, or seconds and microseconds_with_frac since the Epoch. seconds_with_frac and microseconds_with_frac can be an Integer, Float, Rational, or other Numeric.
If in argument is given, the result is in that timezone or UTC offset, or if a numeric argument is given, the result is in local time. The in argument accepts the same types of arguments as tz argument of Time.new: string, number of seconds, or a timezone object.
Time.at(0) #=> 1969-12-31 18:00:00 -0600 Time.at(Time.at(0)) #=> 1969-12-31 18:00:00 -0600 Time.at(946702800) #=> 1999-12-31 23:00:00 -0600 Time.at(-284061600) #=> 1960-12-31 00:00:00 -0600 Time.at(946684800.2).usec #=> 200000 Time.at(946684800, 123456.789).nsec #=> 123456789 Time.at(946684800, 123456789, :nsec).nsec #=> 123456789 Time.at(1582721899, in: "+09:00") #=> 2020-02-26 21:58:19 +0900 Time.at(1582721899, in: "UTC") #=> 2020-02-26 12:58:19 UTC Time.at(1582721899, in: "C") #=> 2020-02-26 13:58:19 +0300 Time.at(1582721899, in: 32400) #=> 2020-02-26 21:58:19 +0900 require 'tzinfo' Time.at(1582721899, in: TZInfo::Timezone.get('Europe/Kiev')) #=> 2020-02-26 14:58:19 +0200
Creates a Time object based on given values, interpreted as UTC (GMT). The year must be specified. Other values default to the minimum value for that field (and may be nil or omitted). Months may be specified by numbers from 1 to 12, or by the three-letter English month names. Hours are specified on a 24-hour clock (0..23). Raises an ArgumentError if any values are out of range. Will also accept ten arguments in the order output by Time#to_a.
sec_with_frac and usec_with_frac can have a fractional part.
Time.utc(2000,"jan",1,20,15,1) #=> 2000-01-01 20:15:01 UTC Time.gm(2000,"jan",1,20,15,1) #=> 2000-01-01 20:15:01 UTC
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
Calls the block once for each [key, value] pair in the database. Returns self.
Updates the database with multiple values from the specified object. Takes any object which implements the each_pair method, including Hash and DBM objects.
Yields the value of each struct member in order. If no block is given an enumerator is returned.
Customer = Struct.new(:name, :address, :zip) joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345) joe.each {|x| puts(x) }
Produces:
Joe Smith 123 Maple, Anytown NC 12345
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