Results for: "to_proc"

Returns a new Array formed from self with elements rotated from one end to the other.

When no argument given, returns a new Array that is like self, except that the first element has been rotated to the last position:

a = [:foo, 'bar', 2, 'bar']
a1 = a.rotate
a1 # => ["bar", 2, "bar", :foo]

When given a non-negative Integer count, returns a new Array with count elements rotated from the beginning to the end:

a = [:foo, 'bar', 2]
a1 = a.rotate(2)
a1 # => [2, :foo, "bar"]

If count is large, uses count % array.size as the count:

a = [:foo, 'bar', 2]
a1 = a.rotate(20)
a1 # => [2, :foo, "bar"]

If count is zero, returns a copy of self, unmodified:

a = [:foo, 'bar', 2]
a1 = a.rotate(0)
a1 # => [:foo, "bar", 2]

When given a negative Integer count, rotates in the opposite direction, from end to beginning:

a = [:foo, 'bar', 2]
a1 = a.rotate(-2)
a1 # => ["bar", 2, :foo]

If count is small (far from zero), uses count % array.size as the count:

a = [:foo, 'bar', 2]
a1 = a.rotate(-5)
a1 # => ["bar", 2, :foo]

Rotates self in place by moving elements from one end to the other; returns self.

When no argument given, rotates the first element to the last position:

a = [:foo, 'bar', 2, 'bar']
a.rotate! # => ["bar", 2, "bar", :foo]

When given a non-negative Integer count, rotates count elements from the beginning to the end:

a = [:foo, 'bar', 2]
a.rotate!(2)
a # => [2, :foo, "bar"]

If count is large, uses count % array.size as the count:

a = [:foo, 'bar', 2]
a.rotate!(20)
a # => [2, :foo, "bar"]

If count is zero, returns self unmodified:

a = [:foo, 'bar', 2]
a.rotate!(0)
a # => [:foo, "bar", 2]

When given a negative Integer count, rotates in the opposite direction, from end to beginning:

a = [:foo, 'bar', 2]
a.rotate!(-2)
a # => ["bar", 2, :foo]

If count is small (far from zero), uses count % array.size as the count:

a = [:foo, 'bar', 2]
a.rotate!(-5)
a # => ["bar", 2, :foo]

Returns the first element in self that is an Array whose first element == obj:

a = [{foo: 0}, [2, 4], [4, 5, 6], [4, 5]]
a.assoc(4) # => [4, 5, 6]

Returns nil if no such element is found.

Related: rassoc.

Returns the first element in self that is an Array whose second element == obj:

a = [{foo: 0}, [2, 4], [4, 5, 6], [4, 5]]
a.rassoc(4) # => [2, 4]

Returns nil if no such element is found.

Related: assoc.

Returns a new Array containing all but the first n element of self, where n is a non-negative Integer; does not modify self.

Examples:

a = [0, 1, 2, 3, 4, 5]
a.drop(0) # => [0, 1, 2, 3, 4, 5]
a.drop(1) # => [1, 2, 3, 4, 5]
a.drop(2) # => [2, 3, 4, 5]

Prepends the given objects to self:

a = [:foo, 'bar', 2]
a.unshift(:bam, :bat) # => [:bam, :bat, :foo, "bar", 2]

Related: push, pop, shift.

Returns the predecessor of self (equivalent to self - 1):

1.pred  #=> 0
-1.pred #=> -2

Related: Integer#succ (successor value).

Returns self rounded to the nearest value with a precision of ndigits decimal digits.

When ndigits is negative, the returned value has at least ndigits.abs trailing zeros:

555.round(-1)      # => 560
555.round(-2)      # => 600
555.round(-3)      # => 1000
-555.round(-2)     # => -600
555.round(-4)      # => 0

Returns self when ndigits is zero or positive.

555.round     # => 555
555.round(1)  # => 555
555.round(50) # => 555

If keyword argument half is given, and self is equidistant from the two candidate values, the rounding is according to the given half value:

• :up or nil: round away from zero:

  25.round(-1, half: :up)      # => 30
  (-25).round(-1, half: :up)   # => -30
  

• :down: round toward zero:

  25.round(-1, half: :down)    # => 20
  (-25).round(-1, half: :down) # => -20
  

• :even: round toward the candidate whose last nonzero digit is even:

  25.round(-1, half: :even)    # => 20
  15.round(-1, half: :even)    # => 20
  (-25).round(-1, half: :even) # => -20
  

Raises and exception if the value for half is invalid.

Related: Integer#truncate.

Returns true if self has a zero value, false otherwise.

Returns true if zero has a zero value, false otherwise.

Of the Core and Standard Library classes, only Rational and Complex use this implementation.

Returns self if self is not a zero value, nil otherwise; uses method zero? for the evaluation.

The returned self allows the method to be chained:

a = %w[z Bb bB bb BB a aA Aa AA A]
a.sort {|a, b| (a.downcase <=> b.downcase).nonzero? || a <=> b }
# => ["A", "a", "AA", "Aa", "aA", "BB", "Bb", "bB", "bb", "z"]

Of the Core and Standard Library classes, Integer, Float, Rational, and Complex use this implementation.

Returns self rounded to the nearest value with a precision of digits decimal digits.

Numeric implements this by converting self to a Float and invoking Float#round.

Interprets the leading substring of self as a string of octal digits (with an optional sign) and returns the corresponding number; returns zero if there is no such leading substring:

'123'.oct             # => 83
'-377'.oct            # => -255
'0377non-numeric'.oct # => 255
'non-numeric'.oct     # => 0

If self starts with 0, radix indicators are honored; see Kernel#Integer.

Related: String#hex.

Prepends each string in other_strings to self and returns self:

s = 'foo'
s.prepend('bar', 'baz') # => "barbazfoo"
s                       # => "barbazfoo"

Related: String#concat.

Returns self rounded to the nearest value with a precision of ndigits decimal digits.

When ndigits is non-negative, returns a float with ndigits after the decimal point (as available):

f = 12345.6789
f.round(1) # => 12345.7
f.round(3) # => 12345.679
f = -12345.6789
f.round(1) # => -12345.7
f.round(3) # => -12345.679

When ndigits is negative, returns an integer with at least ndigits.abs trailing zeros:

f = 12345.6789
f.round(0)  # => 12346
f.round(-3) # => 12000
f = -12345.6789
f.round(0)  # => -12346
f.round(-3) # => -12000

If keyword argument half is given, and self is equidistant from the two candidate values, the rounding is according to the given half value:

• :up or nil: round away from zero:

  2.5.round(half: :up)      # => 3
  3.5.round(half: :up)      # => 4
  (-2.5).round(half: :up)   # => -3
  

• :down: round toward zero:

  2.5.round(half: :down)    # => 2
  3.5.round(half: :down)    # => 3
  (-2.5).round(half: :down) # => -2
  

• :even: round toward the candidate whose last nonzero digit is even:

  2.5.round(half: :even)    # => 2
  3.5.round(half: :even)    # => 4
  (-2.5).round(half: :even) # => -2
  

Raises and exception if the value for half is invalid.

Related: Float#truncate.

Returns true if self is 0.0, false otherwise.

Forces the fiber to be blocking for the duration of the block. Returns the result of the block.

See the “Non-blocking fibers” section in class docs for details.

Returns true if fiber is blocking and false otherwise. Fiber is non-blocking if it was created via passing blocking: false to Fiber.new, or via Fiber.schedule.

Note that, even if the method returns false, the fiber behaves differently only if Fiber.scheduler is set in the current thread.

See the “Non-blocking fibers” section in class docs for details.

Returns false if the current fiber is non-blocking. Fiber is non-blocking if it was created via passing blocking: false to Fiber.new, or via Fiber.schedule.

If the current Fiber is blocking, the method returns 1. Future developments may allow for situations where larger integers could be returned.

Note that, even if the method returns false, Fiber behaves differently only if Fiber.scheduler is set in the current thread.

See the “Non-blocking fibers” section in class docs for details.

Changes the root directory of the calling process to that specified in dirpath. The new root directory is used for pathnames beginning with '/'. The root directory is inherited by all children of the calling process.

Only a privileged process may call chroot.

See Linux chroot.

Locks or unlocks a file according to the given locking_constant, a bitwise OR of the values in the table below.

Not available on all platforms.

Returns false if File::LOCK_NB is specified and the operation would have blocked; otherwise returns 0.

Example:

# Update a counter using an exclusive lock.
# Don't use File::WRONLY because it truncates the file.
File.open('counter', File::RDWR | File::CREAT, 0644) do |f|
  f.flock(File::LOCK_EX)
  value = f.read.to_i + 1
  f.rewind
  f.write("#{value}\n")
  f.flush
  f.truncate(f.pos)
end

# Read the counter using a shared lock.
File.open('counter', 'r') do |f|
  f.flock(File::LOCK_SH)
  f.read
end