Returns a new array containing each element in self that is #eql? to at least one element in each of the given other_arrays; duplicates are omitted:
[0, 0, 1, 1, 2, 3].intersection([0, 1, 2], [0, 1, 3]) # => [0, 1]
Each element must correctly implement method #hash.
Order from self is preserved:
[0, 1, 2].intersection([2, 1, 0]) # => [0, 1, 2]
Returns a copy of self if no arguments are given.
Related: see Methods for Combining.
Returns whether other_array has at least one element that is #eql? to some element of self:
[1, 2, 3].intersect?([3, 4, 5]) # => true [1, 2, 3].intersect?([4, 5, 6]) # => false
Each element must correctly implement method #hash.
Related: see Methods for Querying.
Inserts the given objects as elements of self; returns self.
When index is non-negative, inserts objects before the element at offset index:
a = ['a', 'b', 'c'] # => ["a", "b", "c"] a.insert(1, :x, :y, :z) # => ["a", :x, :y, :z, "b", "c"]
Extends the array if index is beyond the array (index >= self.size):
a = ['a', 'b', 'c'] # => ["a", "b", "c"] a.insert(5, :x, :y, :z) # => ["a", "b", "c", nil, nil, :x, :y, :z]
When index is negative, inserts objects after the element at offset index + self.size:
a = ['a', 'b', 'c'] # => ["a", "b", "c"] a.insert(-2, :x, :y, :z) # => ["a", "b", :x, :y, :z, "c"]
With no objects given, does nothing:
a = ['a', 'b', 'c'] # => ["a", "b", "c"] a.insert(1) # => ["a", "b", "c"] a.insert(50) # => ["a", "b", "c"] a.insert(-50) # => ["a", "b", "c"]
Raises IndexError if objects are given and index is negative and out of range.
Related: see Methods for Assigning.
Returns a new array containing the elements of self in reverse order:
[0, 1, 2].reverse # => [2, 1, 0]
Related: see Methods for Combining.
Reverses the order of the elements of self; returns self:
a = [0, 1, 2] a.reverse! # => [2, 1, 0] a # => [2, 1, 0]
Related: see Methods for Assigning.
With a block given, calls the block with each element of self; returns a new array containing those elements of self for which the block returns a truthy value:
a = [:foo, 'bar', 2, :bam] a.select {|element| element.to_s.start_with?('b') } # => ["bar", :bam]
With no block given, returns a new Enumerator.
Related: see Methods for Fetching.
With a block given, calls the block with each element of self; removes from self those elements for which the block returns false or nil.
Returns self if any elements were removed:
a = [:foo, 'bar', 2, :bam] a.select! {|element| element.to_s.start_with?('b') } # => ["bar", :bam]
Returns nil if no elements were removed.
With no block given, returns a new Enumerator.
Related: see Methods for Deleting.
Iterates over permutations of the elements of self; the order of permutations is indeterminate.
With a block and an in-range positive integer argument count (0 < count <= self.size) given, calls the block with each permutation of self of size count; returns self:
a = [0, 1, 2] perms = [] a.permutation(1) {|perm| perms.push(perm) } perms # => [[0], [1], [2]] perms = [] a.permutation(2) {|perm| perms.push(perm) } perms # => [[0, 1], [0, 2], [1, 0], [1, 2], [2, 0], [2, 1]] perms = [] a.permutation(3) {|perm| perms.push(perm) } perms # => [[0, 1, 2], [0, 2, 1], [1, 0, 2], [1, 2, 0], [2, 0, 1], [2, 1, 0]]
When count is zero, calls the block once with a new empty array:
perms = [] a.permutation(0) {|perm| perms.push(perm) } perms # => [[]]
When count is out of range (negative or larger than self.size), does not call the block:
a.permutation(-1) {|permutation| fail 'Cannot happen' } a.permutation(4) {|permutation| fail 'Cannot happen' }
With no block given, returns a new Enumerator.
Related: Methods for Iterating.
Returns an array with both a numeric and a int represented as Integer objects or Float objects.
This is achieved by converting numeric to an Integer or a Float.
A TypeError is raised if the numeric is not an Integer or a Float type.
(0x3FFFFFFFFFFFFFFF+1).coerce(42) #=> [42, 4611686018427387904]
Returns an integer that is a “floor” value for self, as specified by the given ndigits, which must be an integer-convertible object.
When self is zero, returns zero (regardless of the value of ndigits):
0.floor(2) # => 0 0.floor(-2) # => 0
When self is non-zero and ndigits is non-negative, returns self:
555.floor # => 555 555.floor(50) # => 555
When self is non-zero and ndigits is negative, returns a value based on a computed granularity:
The granularity is 10 ** ndigits.abs.
The returned value is the largest multiple of the granularity that is less than or equal to self.
Examples with positive self:
| ndigits | Granularity | 1234.floor(ndigits) |
|---|---|---|
| -1 | 10 | 1230 |
| -2 | 100 | 1200 |
| -3 | 1000 | 1000 |
| -4 | 10000 | 0 |
| -5 | 100000 | 0 |
Examples with negative self:
| ndigits | Granularity | -1234.floor(ndigits) |
|---|---|---|
| -1 | 10 | -1240 |
| -2 | 100 | -1300 |
| -3 | 1000 | -2000 |
| -4 | 10000 | -10000 |
| -5 | 100000 | -100000 |
Related: Integer#ceil.
Returns self modulo other as a real number.
For integer n and real number r, these expressions are equivalent:
n % r n-r*(n/r).floor n.divmod(r)[1]
See Numeric#divmod.
Examples:
10 % 2 # => 0 10 % 3 # => 1 10 % 4 # => 2 10 % -2 # => 0 10 % -3 # => -2 10 % -4 # => -2 10 % 3.0 # => 1.0 10 % Rational(3, 1) # => (1/1)
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 true if self has a zero value, false otherwise.
Returns self.
Return the class or module refined by the receiver.
module M refine String do end end M.refinements[0].target # => String
Returns the Complex object created from the numerators of the real and imaginary parts of self, after converting each part to the lowest common denominator of the two:
c = Complex.rect(Rational(2, 3), Rational(3, 4)) # => ((2/3)+(3/4)*i) c.numerator # => (8+9i)
In this example, the lowest common denominator of the two parts is 12; the two converted parts may be thought of as Rational(8, 12) and Rational(9, 12), whose numerators, respectively, are 8 and 9; so the returned value of c.numerator is Complex.rect(8, 9).
Related: Complex#denominator.
Returns a 2-element array containing two numeric elements, formed from the two operands self and other, of a common compatible type.
Of the Core and Standard Library classes, Integer, Rational, and Complex use this implementation.
Examples:
i = 2 # => 2 i.coerce(3) # => [3, 2] i.coerce(3.0) # => [3.0, 2.0] i.coerce(Rational(1, 2)) # => [0.5, 2.0] i.coerce(Complex(3, 4)) # Raises RangeError. r = Rational(5, 2) # => (5/2) r.coerce(2) # => [(2/1), (5/2)] r.coerce(2.0) # => [2.0, 2.5] r.coerce(Rational(2, 3)) # => [(2/3), (5/2)] r.coerce(Complex(3, 4)) # => [(3+4i), ((5/2)+0i)] c = Complex(2, 3) # => (2+3i) c.coerce(2) # => [(2+0i), (2+3i)] c.coerce(2.0) # => [(2.0+0i), (2+3i)] c.coerce(Rational(1, 2)) # => [((1/2)+0i), (2+3i)] c.coerce(Complex(3, 4)) # => [(3+4i), (2+3i)]
Raises an exception if any type conversion fails.
Returns self.
Raises an exception if the value for freeze is neither true nor nil.
Related: Numeric#dup.
Returns self modulo other as a real number.
Of the Core and Standard Library classes, only Rational uses this implementation.
For Rational r and real number n, these expressions are equivalent:
r % n r-n*(r/n).floor r.divmod(n)[1]
See Numeric#divmod.
Examples:
r = Rational(1, 2) # => (1/2) r2 = Rational(2, 3) # => (2/3) r % r2 # => (1/2) r % 2 # => (1/2) r % 2.0 # => 0.5 r = Rational(301,100) # => (301/100) r2 = Rational(7,5) # => (7/5) r % r2 # => (21/100) r % -r2 # => (-119/100) (-r) % r2 # => (119/100) (-r) %-r2 # => (-21/100)
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 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 <tt>zero?</tt> 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.
Related: zero?
Returns the largest float or integer that is less than or equal to self, as specified by the given ‘ndigits`, which must be an integer-convertible object.
Equivalent to self.to_f.floor(ndigits).
Related: ceil, Float#floor.
Returns the numerator.
Inserts the given other_string into self; returns self.
If the Integer index is positive, inserts other_string at offset index:
'foo'.insert(1, 'bar') # => "fbaroo"
If the Integer index is negative, counts backward from the end of self and inserts other_string at offset index+1 (that is, after self[index]):
'foo'.insert(-2, 'bar') # => "fobaro"