Returns the number of decimal digits in self:
BigDecimal("0").precision # => 0 BigDecimal("1").precision # => 1 BigDecimal("1.1").precision # => 2 BigDecimal("3.1415").precision # => 5 BigDecimal("-1e20").precision # => 21 BigDecimal("1e-20").precision # => 20 BigDecimal("Infinity").precision # => 0 BigDecimal("-Infinity").precision # => 0 BigDecimal("NaN").precision # => 0
Round to the nearest integer (by default), returning the result as a BigDecimal if n is specified, or as an Integer if it isn’t.
BigDecimal('3.14159').round #=> 3 BigDecimal('8.7').round #=> 9 BigDecimal('-9.9').round #=> -10 BigDecimal('3.14159').round(2).class.name #=> "BigDecimal" BigDecimal('3.14159').round.class.name #=> "Integer"
If n is specified and positive, the fractional part of the result has no more than that many digits.
If n is specified and negative, at least that many digits to the left of the decimal point will be 0 in the result, and return value will be an Integer.
BigDecimal('3.14159').round(3) #=> 3.142 BigDecimal('13345.234').round(-2) #=> 13300
The value of the optional mode argument can be used to determine how rounding is performed; see BigDecimal.mode.
Returns True if the value is zero.
Returns self if the value is non-zero, nil otherwise.
Returns rat rounded to the nearest value with 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).round #=> 3 Rational(2, 3).round #=> 1 Rational(-3, 2).round #=> -2 # decimal - 1 2 3 . 4 5 6 # ^ ^ ^ ^ ^ ^ # precision -3 -2 -1 0 +1 +2 Rational('-123.456').round(+1).to_f #=> -123.5 Rational('-123.456').round(-1) #=> -120
The optional half keyword argument is available similar to Float#round.
Rational(25, 100).round(1, half: :up) #=> (3/10) Rational(25, 100).round(1, half: :down) #=> (1/5) Rational(25, 100).round(1, half: :even) #=> (1/5) Rational(35, 100).round(1, half: :up) #=> (2/5) Rational(35, 100).round(1, half: :down) #=> (3/10) Rational(35, 100).round(1, half: :even) #=> (2/5) Rational(-25, 100).round(1, half: :up) #=> (-3/10) Rational(-25, 100).round(1, half: :down) #=> (-1/5) Rational(-25, 100).round(1, half: :even) #=> (-1/5)
Print an argument or list of arguments to the default output stream
cgi = CGI.new cgi.print # default: cgi.print == $DEFAULT_OUTPUT.print
Returns a new Time object based the on given arguments; its timezone is the local timezone.
In the first form (up to seven arguments), argument year is required.
Time.local(2000) # => 2000-01-01 00:00:00 -0600 Time.local(0, 1, 2, 3, 4, 5, 6.5) # => 0000-01-02 03:04:05.0000065 -0600
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 those 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.local(*array) # => 2000-04-24 13:26:57 -0500
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.mktime.
Related: Time.utc.
Converts time to local time (using the local time zone in effect at the creation time of time) modifying the receiver.
If utc_offset is given, it is used instead of the local time.
t = Time.utc(2000, "jan", 1, 20, 15, 1) #=> 2000-01-01 20:15:01 UTC t.utc? #=> true t.localtime #=> 2000-01-01 14:15:01 -0600 t.utc? #=> false t.localtime("+09:00") #=> 2000-01-02 05:15:01 +0900 t.utc? #=> false
If utc_offset is not given and time is local time, just returns the receiver.
Returns a new Time object representing time in local time (using the local time zone in effect for this process).
If utc_offset is given, it is used instead of the local time. utc_offset can be given as a human-readable string (eg. "+09:00") or as a number of seconds (eg. 32400).
t = Time.utc(2000,1,1,20,15,1) #=> 2000-01-01 20:15:01 UTC t.utc? #=> true l = t.getlocal #=> 2000-01-01 14:15:01 -0600 l.utc? #=> false t == l #=> true j = t.getlocal("+09:00") #=> 2000-01-02 05:15:01 +0900 j.utc? #=> false t == j #=> true k = t.getlocal(9*60*60) #=> 2000-01-02 05:15:01 +0900 k.utc? #=> false t == k #=> true
Rounds subsecond to a given precision in decimal digits (0 digits by default). It returns a new Time object. ndigits should be zero or a positive integer.
t = Time.utc(2010,3,30, 5,43,25.123456789r) t #=> 2010-03-30 05:43:25.123456789 UTC t.round #=> 2010-03-30 05:43:25 UTC t.round(0) #=> 2010-03-30 05:43:25 UTC t.round(1) #=> 2010-03-30 05:43:25.1 UTC t.round(2) #=> 2010-03-30 05:43:25.12 UTC t.round(3) #=> 2010-03-30 05:43:25.123 UTC t.round(4) #=> 2010-03-30 05:43:25.1235 UTC t = Time.utc(1999,12,31, 23,59,59) (t + 0.4).round #=> 1999-12-31 23:59:59 UTC (t + 0.49).round #=> 1999-12-31 23:59:59 UTC (t + 0.5).round #=> 2000-01-01 00:00:00 UTC (t + 1.4).round #=> 2000-01-01 00:00:00 UTC (t + 1.49).round #=> 2000-01-01 00:00:00 UTC (t + 1.5).round #=> 2000-01-01 00:00:01 UTC t = Time.utc(1999,12,31, 23,59,59) #=> 1999-12-31 23:59:59 UTC (t + 0.123456789).round(4).iso8601(6) #=> 1999-12-31 23:59:59.1235 UTC
Returns true if an IO object is in non-blocking mode.
Enables non-blocking mode on a stream when set to true, and blocking mode when set to false.
Yields self in non-blocking mode.
When false is given as an argument, self is yielded in blocking mode. The original mode is restored after the block is executed.
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.
Reads maxlen bytes from ios using the pread system call and returns them as a string without modifying the underlying descriptor offset. This is advantageous compared to combining IO#seek and IO#read in that it is atomic, allowing multiple threads/process to share the same IO object for reading the file at various locations. This bypasses any userspace buffering of the IO layer. If the optional outbuf argument is present, it must reference a String, which will receive the data. Raises SystemCallError on error, EOFError at end of file and NotImplementedError if platform does not implement the system call.
File.write("testfile", "This is line one\nThis is line two\n") File.open("testfile") do |f| p f.read # => "This is line one\nThis is line two\n" p f.pread(12, 0) # => "This is line" p f.pread(9, 8) # => "line one\n" end
Provides a mechanism for issuing low-level commands to control or query I/O devices. Arguments and results are platform dependent. If arg is a number, its value is passed directly. If it is a string, it is interpreted as a binary sequence of bytes. On Unix platforms, see ioctl(2) for details. Not implemented on all platforms.
Allocates space for a new object of class’s class and does not call initialize on the new instance. The returned object must be an instance of class.
klass = Class.new do def initialize(*args) @initialized = true end def initialized? @initialized || false end end klass.allocate.initialized? #=> false
Predicate method for root directories. Returns true if the pathname consists of consecutive slashes.
It doesn’t access the filesystem. So it may return false for some pathnames which points to roots such as /usr/...
Return true if parsed source has errors.