Returns:
1, if self is Infinity.
-1 if self is -Infinity.
nil, otherwise.
Examples:
f = 1.0/0.0 # => Infinity f.infinite? # => 1 f = -1.0/0.0 # => -Infinity f.infinite? # => -1 f = 1.0 # => 1.0 f.infinite? # => nil f = 0.0/0.0 # => NaN f.infinite? # => nil
Returns true if self is not Infinity, -Infinity, or Nan, false otherwise:
f = 2.0 # => 2.0 f.finite? # => true f = 1.0/0.0 # => Infinity f.finite? # => false f = -1.0/0.0 # => -Infinity f.finite? # => false f = 0.0/0.0 # => NaN f.finite? # => false
Deletes the named directory. Raises a subclass of SystemCallError if the directory isn’t empty.
Deletes the named files, returning the number of names passed as arguments. Raises an exception on any error. Since the underlying implementation relies on the unlink(2) system call, the type of exception raised depends on its error type (see linux.die.net/man/2/unlink) and has the form of e.g. Errno::ENOENT.
See also Dir::rmdir.
Truncates the file file_name to be at most integer bytes long. Not available on all platforms.
f = File.new("out", "w") f.write("1234567890") #=> 10 f.close #=> nil File.truncate("out", 5) #=> 0 File.size("out") #=> 5
Truncates file to at most integer bytes. The file must be opened for writing. Not available on all platforms.
f = File.new("out", "w") f.syswrite("1234567890") #=> 10 f.truncate(5) #=> 0 f.close() #=> nil File.size("out") #=> 5
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 nil, -1, or +1 depending on whether the value is finite, -Infinity, or +Infinity.
Returns True if the value is finite (not NaN or infinite).
Truncate to the nearest integer (by default), returning the result as a BigDecimal.
BigDecimal('3.14159').truncate #=> 3 BigDecimal('8.7').truncate #=> 8 BigDecimal('-9.9').truncate #=> -9
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.
BigDecimal('3.14159').truncate(3) #=> 3.141 BigDecimal('13345.234').truncate(-2) #=> 13300.0
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 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)
Returns true if the date is Sunday.
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 time represents Sunday.
t = Time.local(1990, 4, 1) #=> 1990-04-01 00:00:00 -0600 t.sunday? #=> true
Pushes back bytes (passed as a parameter) onto ios, such that a subsequent buffered read will return it. It is only guaranteed to support a single byte, and only if ungetbyte or ungetc has not already been called on ios since the previous read of at least a single byte from ios. However, it can support additional bytes if there is space in the internal buffer to allow for it.
f = File.new("testfile") #=> #<File:testfile> b = f.getbyte #=> 0x38 f.ungetbyte(b) #=> nil f.getbyte #=> 0x38
If given an integer, only uses the lower 8 bits of the integer as the byte to push.
f = File.new("testfile") #=> #<File:testfile> f.ungetbyte(0x102) #=> nil f.getbyte #=> 0x2
Calling this method prepends to the existing buffer, even if the method has already been called previously:
f = File.new("testfile") #=> #<File:testfile> f.ungetbyte("ab") #=> nil f.ungetbyte("cd") #=> nil f.read(5) #=> "cdab8"
Has no effect with unbuffered reads (such as IO#sysread).
Pushes back characters (passed as a parameter) onto ios, such that a subsequent buffered read will return it. It is only guaranteed to support a single byte, and only if ungetbyte or ungetc has not already been called on ios since the previous read of at least a single byte from ios. However, it can support additional bytes if there is space in the internal buffer to allow for it.
f = File.new("testfile") #=> #<File:testfile> c = f.getc #=> "8" f.ungetc(c) #=> nil f.getc #=> "8"
If given an integer, the integer must represent a valid codepoint in the external encoding of ios.
Calling this method prepends to the existing buffer, even if the method has already been called previously:
f = File.new("testfile") #=> #<File:testfile> f.ungetc("ab") #=> nil f.ungetc("cd") #=> nil f.read(5) #=> "cdab8"
Has no effect with unbuffered reads (such as IO#sysread).
Returns the count of elements, based on an argument or block criterion, if given.
With no argument and no block given, returns the number of elements:
(1..4).count # => 4 (1...4).count # => 3 ('a'..'d').count # => 4 ('a'...'d').count # => 3 (1..).count # => Infinity (..4).count # => Infinity
With argument object, returns the number of object found in self, which will usually be zero or one:
(1..4).count(2) # => 1 (1..4).count(5) # => 0 (1..4).count('a') # => 0
With a block given, calls the block with each element; returns the number of elements for which the block returns a truthy value:
(1..4).count {|element| element < 3 } # => 2
Related: Range#size.
Returns true if self points to a mountpoint.
Returns pathname. This method is deprecated and will be removed in Ruby 3.2.