Calls the block, if given, with combinations of elements of self; returns self. The order of combinations is indeterminate.
When a block and an in-range positive Integer argument n (0 < n <= self.size) are given, calls the block with all n-tuple combinations of self.
Example:
a = [0, 1, 2] a.combination(2) {|combination| p combination }
Output:
[0, 1] [0, 2] [1, 2]
Another example:
a = [0, 1, 2] a.combination(3) {|combination| p combination }
Output:
[0, 1, 2]
When n is zero, calls the block once with a new empty Array:
a = [0, 1, 2] a1 = a.combination(0) {|combination| p combination }
Output:
[]
When n is out of range (negative or larger than self.size), does not call the block:
a = [0, 1, 2] a.combination(-1) {|combination| fail 'Cannot happen' } a.combination(4) {|combination| fail 'Cannot happen' }
Returns a new Enumerator if no block given:
a = [0, 1, 2] a.combination(2) # => #<Enumerator: [0, 1, 2]:combination(2)>
Returns elements from self; does not modify self.
When no argument is given, returns the first element:
a = [:foo, 'bar', 2] a.first # => :foo a # => [:foo, "bar", 2]
If self is empty, returns nil.
When non-negative Integer argument n is given, returns the first n elements in a new Array:
a = [:foo, 'bar', 2] a.first(2) # => [:foo, "bar"]
If n >= array.size, returns all elements:
a = [:foo, 'bar', 2] a.first(50) # => [:foo, "bar", 2]
If n == 0 returns an new empty Array:
a = [:foo, 'bar', 2] a.first(0) # []
Related: last.
Returns elements from self; self is not modified.
When no argument is given, returns the last element:
a = [:foo, 'bar', 2] a.last # => 2 a # => [:foo, "bar", 2]
If self is empty, returns nil.
When non-negative Integer argument n is given, returns the last n elements in a new Array:
a = [:foo, 'bar', 2] a.last(2) # => ["bar", 2]
If n >= array.size, returns all elements:
a = [:foo, 'bar', 2] a.last(50) # => [:foo, "bar", 2]
If n == 0, returns an new empty Array:
a = [:foo, 'bar', 2] a.last(0) # []
Related: first.
Builds a command line string from an argument list array joining all elements escaped for the Bourne shell and separated by a space.
See Shellwords.shelljoin for details.
Returns a Hash containing implementation-dependent counters inside the VM.
This hash includes information about method/constant caches:
{
:constant_cache_invalidations=>2,
:constant_cache_misses=>14,
:global_cvar_state=>27
}
If USE_DEBUG_COUNTER is enabled, debug counters will be included.
The contents of the hash are implementation specific and may be changed in the future.
This method is only expected to work on C Ruby.
Returns self truncated (toward zero) to a precision of ndigits decimal digits.
When ndigits is negative, the returned value has at least ndigits.abs trailing zeros:
555.truncate(-1) # => 550 555.truncate(-2) # => 500 -555.truncate(-2) # => -500
Returns self when ndigits is zero or positive.
555.truncate # => 555 555.truncate(50) # => 555
Related: Integer#round.
Returns the remainder after dividing self by other.
Examples:
11.remainder(4) # => 3 11.remainder(-4) # => 3 -11.remainder(4) # => -3 -11.remainder(-4) # => -3 12.remainder(4) # => 0 12.remainder(-4) # => 0 -12.remainder(4) # => 0 -12.remainder(-4) # => 0 13.remainder(4.0) # => 1.0 13.remainder(Rational(4, 1)) # => (1/1)
Returns a string containing the place-value representation of self in radix base (in 2..36).
12345.to_s # => "12345" 12345.to_s(2) # => "11000000111001" 12345.to_s(8) # => "30071" 12345.to_s(10) # => "12345" 12345.to_s(16) # => "3039" 12345.to_s(36) # => "9ix" 78546939656932.to_s(36) # => "rubyrules"
Raises an exception if base is out of range.
Since self is already an Integer, always returns true.
Returns 1.
Returns a new Complex object formed from the arguments, each of which must be an instance of Numeric, or an instance of one of its subclasses: Complex, Float, Integer, Rational; see Rectangular Coordinates:
Complex.rect(3) # => (3+0i) Complex.rect(3, Math::PI) # => (3+3.141592653589793i) Complex.rect(-3, -Math::PI) # => (-3-3.141592653589793i)
Complex.rectangular is an alias for Complex.rect.
Returns the imaginary value for self:
Complex(7).imaginary #=> 0 Complex(9, -4).imaginary #=> -4
If self was created with polar coordinates, the returned value is computed, and may be inexact:
Complex.polar(1, Math::PI/4).imag # => 0.7071067811865476 # Square root of 2.
Returns the argument (angle) for self in radians; see polar coordinates:
Complex.polar(3, Math::PI/2).arg # => 1.57079632679489660
If self was created with rectangular coordinates, the returned value is computed, and may be inexact:
Complex.polar(1, 1.0/3).arg # => 0.33333333333333326
Returns the array [self.real, self.imag]:
Complex.rect(1, 2).rect # => [1, 2]
If self was created with polar coordinates, the returned value is computed, and may be inexact:
Complex.polar(1.0, 1.0).rect # => [0.5403023058681398, 0.8414709848078965]
Complex#rectangular is an alias for Complex#rect.
Returns the denominator of self, which is the least common multiple of self.real.denominator and self.imag.denominator:
Complex.rect(Rational(1, 2), Rational(2, 3)).denominator # => 6
Note that n.denominator of a non-rational numeric is 1.
Related: Complex#numerator.
Returns a string representation of self:
Complex(2).inspect # => "(2+0i)" Complex('-8/6').inspect # => "((-4/3)+0i)" Complex('1/2i').inspect # => "(0+(1/2)*i)" Complex(0, Float::INFINITY).inspect # => "(0+Infinity*i)" Complex(Float::NAN, Float::NAN).inspect # => "(NaN+NaN*i)"
Returns true if both self.real.finite? and self.imag.finite? are true, false otherwise:
Complex(1, 1).finite? # => true Complex(Float::INFINITY, 0).finite? # => false
Related: Numeric#finite?, Float#finite?.
Returns zero if self is positive, Math::PI otherwise.
Returns array [self, 0].
Returns the remainder after dividing self by other.
Of the Core and Standard Library classes, only Float and Rational use this implementation.
Examples:
11.0.remainder(4) # => 3.0 11.0.remainder(-4) # => 3.0 -11.0.remainder(4) # => -3.0 -11.0.remainder(-4) # => -3.0 12.0.remainder(4) # => 0.0 12.0.remainder(-4) # => 0.0 -12.0.remainder(4) # => -0.0 -12.0.remainder(-4) # => -0.0 13.0.remainder(4.0) # => 1.0 13.0.remainder(Rational(4, 1)) # => 1.0 Rational(13, 1).remainder(4) # => (1/1) Rational(13, 1).remainder(-4) # => (1/1) Rational(-13, 1).remainder(4) # => (-1/1) Rational(-13, 1).remainder(-4) # => (-1/1)
Returns self truncated (toward zero) to a precision of digits decimal digits.
Numeric implements this by converting self to a Float and invoking Float#truncate.
Generates a sequence of numbers; with a block given, traverses the sequence.
Of the Core and Standard Library classes,
Integer, Float, and Rational use this implementation.
A quick example:
squares = []
1.step(by: 2, to: 10) {|i| squares.push(i*i) }
squares # => [1, 9, 25, 49, 81]
The generated sequence:
- Begins with +self+.
- Continues at intervals of +by+ (which may not be zero).
- Ends with the last number that is within or equal to +to+;
that is, less than or equal to +to+ if +by+ is positive,
greater than or equal to +to+ if +by+ is negative.
If +to+ is +nil+, the sequence is of infinite length.
If a block is given, calls the block with each number in the sequence;
returns +self+. If no block is given, returns an Enumerator::ArithmeticSequence.
<b>Keyword Arguments</b>
With keyword arguments +by+ and +to+,
their values (or defaults) determine the step and limit:
# Both keywords given.
squares = []
4.step(by: 2, to: 10) {|i| squares.push(i*i) } # => 4
squares # => [16, 36, 64, 100]
cubes = []
3.step(by: -1.5, to: -3) {|i| cubes.push(i*i*i) } # => 3
cubes # => [27.0, 3.375, 0.0, -3.375, -27.0]
squares = []
1.2.step(by: 0.2, to: 2.0) {|f| squares.push(f*f) }
squares # => [1.44, 1.9599999999999997, 2.5600000000000005, 3.24, 4.0]
squares = []
Rational(6/5).step(by: 0.2, to: 2.0) {|r| squares.push(r*r) }
squares # => [1.0, 1.44, 1.9599999999999997, 2.5600000000000005, 3.24, 4.0]
# Only keyword to given.
squares = []
4.step(to: 10) {|i| squares.push(i*i) } # => 4
squares # => [16, 25, 36, 49, 64, 81, 100]
# Only by given.
# Only keyword by given
squares = []
4.step(by:2) {|i| squares.push(i*i); break if i > 10 }
squares # => [16, 36, 64, 100, 144]
# No block given.
e = 3.step(by: -1.5, to: -3) # => (3.step(by: -1.5, to: -3))
e.class # => Enumerator::ArithmeticSequence
<b>Positional Arguments</b>
With optional positional arguments +to+ and +by+,
their values (or defaults) determine the step and limit:
squares = []
4.step(10, 2) {|i| squares.push(i*i) } # => 4
squares # => [16, 36, 64, 100]
squares = []
4.step(10) {|i| squares.push(i*i) }
squares # => [16, 25, 36, 49, 64, 81, 100]
squares = []
4.step {|i| squares.push(i*i); break if i > 10 } # => nil
squares # => [16, 25, 36, 49, 64, 81, 100, 121]
Implementation Notes
If all the arguments are integers, the loop operates using an integer counter. If any of the arguments are floating point numbers, all are converted to floats, and the loop is executed <i>floor(n + n*Float::EPSILON) + 1</i> times, where <i>n = (limit - self)/step</i>.
Returns true if self is a finite number, false otherwise.