When invoked with a block, yields all combinations of length n of elements from the array and then returns the array itself.
The implementation makes no guarantees about the order in which the combinations are yielded.
If no block is given, an Enumerator is returned instead.
Examples:
a = [1, 2, 3, 4] a.combination(1).to_a #=> [[1],[2],[3],[4]] a.combination(2).to_a #=> [[1,2],[1,3],[1,4],[2,3],[2,4],[3,4]] a.combination(3).to_a #=> [[1,2,3],[1,2,4],[1,3,4],[2,3,4]] a.combination(4).to_a #=> [[1,2,3,4]] a.combination(0).to_a #=> [[]] # one combination of length 0 a.combination(5).to_a #=> [] # no combinations of length 5
Returns the value as a rational. The optional argument eps is always ignored.
Returns the value as a rational if possible (the imaginary part should be exactly zero).
Complex(1.0/3, 0).rationalize #=> (1/3) Complex(1, 0.0).rationalize # RangeError Complex(1, 2).rationalize # RangeError
See to_r.
Returns zero as a rational. The optional argument eps is always ignored.
Returns a simpler approximation of the value (flt-|eps| <= result <= flt+|eps|). If the optional argument eps is not given, it will be chosen automatically.
0.3.rationalize #=> (3/10) 1.333.rationalize #=> (1333/1000) 1.333.rationalize(0.01) #=> (4/3)
See also Float#to_r.
With no argument, or if the argument is the same as the receiver, return the receiver. Otherwise, create a new exception object of the same class as the receiver, but with a message equal to string.to_str.
With no argument, or if the argument is the same as the receiver, return the receiver. Otherwise, create a new exception object of the same class as the receiver, but with a message equal to string.to_str.
Returns a simpler approximation of the value if the optional argument eps is given (rat-|eps| <= result <= rat+|eps|), self otherwise.
r = Rational(5033165, 16777216) r.rationalize #=> (5033165/16777216) r.rationalize(Rational('0.01')) #=> (3/10) r.rationalize(Rational('0.1')) #=> (1/3)
Return a Regexp object that is the union of the given patterns, i.e., will match any of its parts. The patterns can be Regexp objects, in which case their options will be preserved, or Strings. If no patterns are given, returns /(?!)/. The behavior is unspecified if any given pattern contains capture.
Regexp.union #=> /(?!)/ Regexp.union("penzance") #=> /penzance/ Regexp.union("a+b*c") #=> /a\+b\*c/ Regexp.union("skiing", "sledding") #=> /skiing|sledding/ Regexp.union(["skiing", "sledding"]) #=> /skiing|sledding/ Regexp.union(/dogs/, /cats/i) #=> /(?-mix:dogs)|(?i-mx:cats)/
Note: the arguments for ::union will try to be converted into a regular expression literal via to_regexp.
Returns the set of bits corresponding to the options used when creating this Regexp (see Regexp::new for details. Note that additional bits may be set in the returned options: these are used internally by the regular expression code. These extra bits are ignored if the options are passed to Regexp::new.
Regexp::IGNORECASE #=> 1 Regexp::EXTENDED #=> 2 Regexp::MULTILINE #=> 4 /cat/.options #=> 0 /cat/ix.options #=> 3 Regexp.new('cat', true).options #=> 1 /\xa1\xa2/e.options #=> 16 r = /cat/ix Regexp.new(r.source, r.options) #=> /cat/ix
Returns true if argument is optional.
tobj = WIN32OLE_TYPE.new('Microsoft Excel 9.0 Object Library', 'Workbook') method = WIN32OLE_METHOD.new(tobj, 'SaveAs') param1 = method.params[0] puts "#{param1.name} #{param1.optional?}" # => Filename true
Returns true if this is a permutation matrix Raises an error if matrix is not square.
Returns x/y or arg as a Rational.
Rational(2, 3) #=> (2/3) Rational(5) #=> (5/1) Rational(0.5) #=> (1/2) Rational(0.3) #=> (5404319552844595/18014398509481984) Rational("2/3") #=> (2/3) Rational("0.3") #=> (3/10) Rational("10 cents") #=> ArgumentError Rational(nil) #=> TypeError Rational(1, nil) #=> TypeError Rational("10 cents", exception: false) #=> nil
Syntax of the string form:
string form = extra spaces , rational , extra spaces ;
rational = [ sign ] , unsigned rational ;
unsigned rational = numerator | numerator , "/" , denominator ;
numerator = integer part | fractional part | integer part , fractional part ;
denominator = digits ;
integer part = digits ;
fractional part = "." , digits , [ ( "e" | "E" ) , [ sign ] , digits ] ;
sign = "-" | "+" ;
digits = digit , { digit | "_" , digit } ;
digit = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" ;
extra spaces = ? \s* ? ;
See also String#to_r.
Returns the options bitmask used in the last call to open()
Returns an Array of option names.
p FileUtils.options #=> ["noop", "force", "verbose", "preserve", "mode"]
UNTESTED
Get the names of all sections in the current configuration
Get an array of all Instruction children. IMMUTABLE
Called when an instruction is encountered. EG: <?xsl sheet=‘foo’?> @p name the instruction name; in the example, “xsl” @p instruction the rest of the instruction. In the example, “sheet=‘foo’”