struct Range(B, E)
Overview
A Range represents an interval: a set of values with a beginning and an end.
Ranges may be constructed using the usual .new method or with literals:
x..y # an inclusive range, in mathematics: [x, y]
x...y # an exclusive range, in mathematics: [x, y)
(x..) # an endless range, in mathematics: >= x
..y # a beginless inclusive range, in mathematics: <= y
...y # a beginless exclusive range, in mathematics: < y
See Range literals in the language reference.
An easy way to remember which one is inclusive and which one is exclusive it to think of the extra dot as if it pushes y further away, thus leaving it outside of the range.
Ranges typically involve integers, but can be created using arbitrary objects
as long as they define succ (or pred for #reverse_each), to get the
next element in the range, and < and #==, to know when the range reached the end:
# Represents a string of 'x's.
struct Xs
include Comparable(Xs)
getter size
def initialize(@size : Int32)
end
def succ
Xs.new(@size + 1)
end
def <=>(other)
@size <=> other.size
end
def inspect(io)
@size.times { io << 'x' }
end
def to_s(io)
io << @size << ' '
inspect(io)
end
end
An example of using Xs to construct a range:
r = Xs.new(3)..Xs.new(6)
r.to_s # => "xxx..xxxxxx"
r.to_a # => [Xs.new(3), Xs.new(4), Xs.new(5), Xs.new(6)]
r.includes?(Xs.new(5)) # => true
Included Modules
Defined in:
range.crrange/bsearch.cr
Constructors
-
.new(begin __arg0 : B, end __arg1 : E, exclusive : Bool = false)
Constructs a
Rangeusing the given beginning and end.
Instance Method Summary
- #==(other : Range)
-
#===(value)
Same as
#includes?, useful for thecaseexpression. -
#begin : B
Returns the object that defines the beginning of this range.
-
#bsearch(&block : B | E -> _)
By using binary search, returns the first element for which the passed block returns a truthy value.
- #clone
-
#covers?(value)
Same as
#includes?. -
#cycle
Returns an
Iteratorthat cycles over the values of this range. -
#each(&) : Nil
Iterates over the elements of this range, passing each in turn to the block.
-
#each
Returns an
Iteratorover the elements of this range. -
#end : E
Returns the object that defines the end of the range.
-
#excludes_end? : Bool
Returns
trueif this range excludes the end element. -
#exclusive? : Bool
Returns
trueif the range is exclusive. -
#includes?(value) : Bool
Returns
trueif this range includes the given value. -
#inspect(io : IO) : Nil
Appends this struct's name and instance variables names and values to the given IO.
-
#map(&block : B -> U) forall U
Returns an
Arraywith the results of running the block against each element of the collection. -
#reverse_each(&) : Nil
Iterates over the elements of this range in reverse order, passing each in turn to the block.
-
#reverse_each
Returns a reverse
Iteratorover the elements of this range. -
#sample(random : Random = Random::DEFAULT)
Optimized version of
Enumerable#samplethat runs in O(1) time whenselfis anIntorFloatrange. -
#sample(n : Int, random = Random::DEFAULT)
:inherit:
-
#size : Int32
Returns the number of values in this range.
- #step(by = 1, &) : Nil
- #step(by = 1) : Iterator
-
#sum(initial)
Optimized version of
Enumerable#sumthat runs in O(1) time whenselfis anIntrange. -
#to_s(io : IO) : Nil
Same as
#inspect(io).
Instance methods inherited from module Iterable(B)
chunk(reuse = false, &block : T -> U) forall U
chunk,
chunk_while(reuse : Bool | Array(T) = false, &block : T, T -> B) forall B
chunk_while,
cycle(n)cycle cycle, each each, each_cons(count : Int, reuse = false) each_cons, each_cons_pair each_cons_pair, each_slice(count : Int, reuse = false) each_slice, each_step(n : Int)
each_step(n : Int, *, offset : Int) each_step, each_with_index(offset = 0) each_with_index, each_with_object(obj) each_with_object, slice_after(reuse : Bool | Array(T) = false, &block : T -> B) forall B
slice_after(pattern, reuse : Bool | Array(T) = false) slice_after, slice_before(reuse : Bool | Array(T) = false, &block : T -> B) forall B
slice_before(pattern, reuse : Bool | Array(T) = false) slice_before, slice_when(reuse : Bool | Array(T) = false, &block : T, T -> B) forall B slice_when
Instance methods inherited from module Enumerable(B)
accumulate(initial : U) : Array(U) forall Uaccumulate : Array(T)
accumulate(initial : U, &block : U, T -> U) : Array(U) forall U
accumulate(&block : T, T -> T) : Array(T) accumulate, all?(& : T -> ) : Bool
all?(pattern) : Bool
all? : Bool all?, any?(& : T -> ) : Bool
any?(pattern) : Bool
any? : Bool any?, chunks(&block : T -> U) forall U chunks, compact_map(& : T -> _) compact_map, count(& : T -> ) : Int32
count(item) : Int32 count, cycle(n, & : T -> ) : Nil
cycle(& : T -> ) : Nil cycle, each(& : T -> ) each, each_cons(count : Int, reuse = false, &) each_cons, each_cons_pair(& : T, T -> ) : Nil each_cons_pair, each_slice(count : Int, reuse = false, &) each_slice, each_step(n : Int, *, offset : Int = 0, & : T -> ) : Nil each_step, each_with_index(offset = 0, &) each_with_index, each_with_object(obj : U, & : T, U -> ) : U forall U each_with_object, empty? : Bool empty?, find(if_none = nil, & : T -> ) find, find!(& : T -> ) : T find!, find_value(if_none = nil, & : T -> ) find_value, first(&)
first(count : Int) : Array(T)
first : T first, first? : T | Nil first?, flat_map(& : T -> _) flat_map, group_by(& : T -> U) forall U group_by, in_groups_of(size : Int, filled_up_with : U = nil) forall U
in_groups_of(size : Int, filled_up_with : U = nil, reuse = false, &) forall U in_groups_of, in_slices_of(size : Int) : Array(Array(T)) in_slices_of, includes?(obj) : Bool includes?, index(& : T -> ) : Int32 | Nil
index(obj) : Int32 | Nil index, index!(& : T -> ) : Int32
index!(obj) : Int32 index!, index_by(& : T -> U) : Hash(U, T) forall U index_by, join(io : IO, separator = "") : Nil
join(separator, io : IO) : Nil
join(separator = "") : String
join(io : IO, separator = "", & : T, IO -> )
join(separator, io : IO, &)
join(separator = "", & : T -> ) join, map(& : T -> U) : Array(U) forall U map, map_with_index(offset = 0, & : T, Int32 -> U) : Array(U) forall U map_with_index, max(count : Int) : Array(T)
max : T max, max? : T | Nil max?, max_by(& : T -> U) : T forall U max_by, max_by?(& : T -> U) : T | Nil forall U max_by?, max_of(& : T -> U) : U forall U max_of, max_of?(& : T -> U) : U | Nil forall U max_of?, min(count : Int) : Array(T)
min : T min, min? : T | Nil min?, min_by(& : T -> U) : T forall U min_by, min_by?(& : T -> U) : T | Nil forall U min_by?, min_of(& : T -> U) : U forall U min_of, min_of?(& : T -> U) : U | Nil forall U min_of?, minmax : Tuple(T, T) minmax, minmax? : Tuple(T | Nil, T | Nil) minmax?, minmax_by(& : T -> U) : Tuple(T, T) forall U minmax_by, minmax_by?(& : T -> U) : Tuple(T, T) | Tuple(Nil, Nil) forall U minmax_by?, minmax_of(& : T -> U) : Tuple(U, U) forall U minmax_of, minmax_of?(& : T -> U) : Tuple(U, U) | Tuple(Nil, Nil) forall U minmax_of?, none?(& : T -> ) : Bool
none?(pattern) : Bool
none? : Bool none?, one?(& : T -> ) : Bool
one?(pattern) : Bool
one? : Bool one?, partition(& : T -> ) : Tuple(Array(T), Array(T))
partition(type : U.class) forall U partition, present? : Bool present?, product(initial : Number)
product
product(initial : Number, & : T -> )
product(& : T -> _) product, reduce(memo, &)
reduce(&) reduce, reduce?(&) reduce?, reject(& : T -> )
reject(type : U.class) forall U
reject(pattern) : Array(T) reject, sample(n : Int, random : Random = Random::DEFAULT) : Array(T)
sample(random : Random = Random::DEFAULT) : T sample, select(& : T -> )
select(type : U.class) : Array(U) forall U
select(pattern) : Array(T) select, size : Int32 size, skip(count : Int) skip, skip_while(& : T -> ) : Array(T) skip_while, sum(initial)
sum
sum(initial, & : T -> )
sum(& : T -> ) sum, take_while(& : T -> ) : Array(T) take_while, tally(hash)
tally : Hash(T, Int32) tally, tally_by(hash, &)
tally_by(&block : T -> U) : Hash(U, Int32) forall U tally_by, to_a : Array(T)
to_a(& : T -> U) : Array(U) forall U to_a, to_h
to_h(& : T -> Tuple(K, V)) forall K, V to_h, to_set : Set(T)
to_set(&block : T -> U) : Set(U) forall U to_set, zip(*others : Indexable | Iterable | Iterator, &)
zip(*others : Indexable | Iterable | Iterator) zip, zip?(*others : Indexable | Iterable | Iterator, &)
zip?(*others : Indexable | Iterable | Iterator) zip?
Class methods inherited from module Enumerable(B)
element_type(x)
element_type
Instance methods inherited from struct Struct
==(other) : Bool
==,
hash(hasher)
hash,
inspect(io : IO) : Nil
inspect,
pretty_print(pp) : Nil
pretty_print,
to_s(io : IO) : Nil
to_s
Instance methods inherited from struct Value
==(other : JSON::Any)==(other : YAML::Any)
==(other) ==, dup dup
Instance methods inherited from class Object
! : Bool
!,
!=(other)
!=,
!~(other)
!~,
==(other)
==,
===(other : JSON::Any)===(other : YAML::Any)
===(other) ===, =~(other) =~, as(type : Class) as, as?(type : Class) as?, class class, dup dup, hash(hasher)
hash hash, in?(collection : Object) : Bool
in?(*values : Object) : Bool in?, inspect(io : IO) : Nil
inspect : String inspect, is_a?(type : Class) : Bool is_a?, itself itself, nil? : Bool nil?, not_nil!(message)
not_nil! not_nil!, pretty_inspect(width = 79, newline = "\n", indent = 0) : String pretty_inspect, pretty_print(pp : PrettyPrint) : Nil pretty_print, responds_to?(name : Symbol) : Bool responds_to?, tap(&) tap, to_json(io : IO) : Nil
to_json : String to_json, to_pretty_json(indent : String = " ") : String
to_pretty_json(io : IO, indent : String = " ") : Nil to_pretty_json, to_s(io : IO) : Nil
to_s : String to_s, to_yaml(io : IO) : Nil
to_yaml : String to_yaml, try(&) try, unsafe_as(type : T.class) forall T unsafe_as
Class methods inherited from class Object
from_json(string_or_io, root : String)from_json(string_or_io) from_json, from_yaml(string_or_io : String | IO) from_yaml
Macros inherited from class Object
class_getter(*names, &block)
class_getter,
class_getter!(*names)
class_getter!,
class_getter?(*names, &block)
class_getter?,
class_property(*names, &block)
class_property,
class_property!(*names)
class_property!,
class_property?(*names, &block)
class_property?,
class_setter(*names)
class_setter,
def_clone
def_clone,
def_equals(*fields)
def_equals,
def_equals_and_hash(*fields)
def_equals_and_hash,
def_hash(*fields)
def_hash,
delegate(*methods, to object)
delegate,
forward_missing_to(delegate)
forward_missing_to,
getter(*names, &block)
getter,
getter!(*names)
getter!,
getter?(*names, &block)
getter?,
property(*names, &block)
property,
property!(*names)
property!,
property?(*names, &block)
property?,
setter(*names)
setter
Constructor Detail
Constructs a Range using the given beginning and end.
Range.new(1, 10) # => 1..10
Range.new(1, 10, exclusive: true) # => 1...10
Instance Method Detail
Same as #includes?, useful for the case expression.
case 79
when 1..50 then puts "low"
when 51..75 then puts "medium"
when 76..100 then puts "high"
end
Produces:
high
See also: Object#===.
Returns the object that defines the beginning of this range.
(1..10).begin # => 1
(1...10).begin # => 1
By using binary search, returns the first element for which the passed block returns a truthy value.
If the block returns a falsey value, the element to be found lies behind. If the block returns a truthy value, the element to be found is itself or lies in front.
Returns nil if the block didn't return a truthy value for any element.
(0..10).bsearch { |x| x >= 5 } # => 5
(0..Float64::INFINITY).bsearch { |x| x ** 4 >= 256 } # => 4
Returns an Iterator that cycles over the values of this range.
(1..3).cycle.first(5).to_a # => [1, 2, 3, 1, 2]
Iterates over the elements of this range, passing each in turn to the block.
(10..15).each { |n| print n, ' ' }
# prints: 10 11 12 13 14 15
Returns an Iterator over the elements of this range.
(1..3).each.skip(1).to_a # => [2, 3]
Returns the object that defines the end of the range.
(1..10).end # => 10
(1...10).end # => 10
Returns true if this range excludes the end element.
(1..10).excludes_end? # => false
(1...10).excludes_end? # => true
Returns true if this range includes the given value.
(1..10).includes?(4) # => true
(1..10).includes?(10) # => true
(1..10).includes?(11) # => false
(1...10).includes?(9) # => true
(1...10).includes?(10) # => false
Appends this struct's name and instance variables names and values to the given IO.
struct Point
def initialize(@x : Int32, @y : Int32)
end
end
p1 = Point.new 1, 2
p1.to_s # "Point(@x=1, @y=2)"
p1.inspect # "Point(@x=1, @y=2)"
Returns an Array with the results of running the block against each element of the collection.
[1, 2, 3].map { |i| i * 10 } # => [10, 20, 30]
Iterates over the elements of this range in reverse order, passing each in turn to the block.
(10...15).reverse_each { |n| print n, ' ' }
# prints: 14 13 12 11 10
Returns a reverse Iterator over the elements of this range.
(1..3).reverse_each.skip(1).to_a # => [2, 1]
Optimized version of Enumerable#sample that runs in O(1) time when self
is an Int or Float range. In these cases, this range is considered to be
a distribution of numeric values rather than a collection of elements, and
the method simply calls random.rand(self).
Raises ArgumentError if self is an open range.
:inherit:
If self is not empty and n is equal to 1, calls #sample(random) exactly
once. Thus, random will be left in a different state compared to the
implementation in Enumerable.
Returns the number of values in this range.
If both the beginning and the end of this range are Ints, runs in constant
time instead of linear.
(3..8).size # => 6
(3...8).size # => 5
Raises OverflowError if the difference is bigger than Int32.
Raises ArgumentError if either #begin or #end are nil.
Iterates from #begin to #end incrementing by the amount of step on each
iteration.
ary = [] of Int32
(1..4).step(by: 2) do |x|
ary << x
end
ary # => [1, 3]
(1..4).step(by: 2).to_a # => [1, 3]
(1..4).step(by: 1).to_a # => [1, 2, 3, 4]
(1...4).step(by: 1).to_a # => [1, 2, 3]
If B is a Steppable, implementation is delegated to Steppable#step.
Otherwise #succ method is expected to be defined on #begin and its
successors and iteration is based on calling #succ sequentially
(step times per iteration).
Raises ArgumentError if #begin is nil.
Iterates from #begin to #end incrementing by the amount of step on each
iteration.
ary = [] of Int32
(1..4).step(by: 2) do |x|
ary << x
end
ary # => [1, 3]
(1..4).step(by: 2).to_a # => [1, 3]
(1..4).step(by: 1).to_a # => [1, 2, 3, 4]
(1...4).step(by: 1).to_a # => [1, 2, 3]
If B is a Steppable, implementation is delegated to Steppable#step.
Otherwise #succ method is expected to be defined on #begin and its
successors and iteration is based on calling #succ sequentially
(step times per iteration).
Raises ArgumentError if #begin is nil.
Optimized version of Enumerable#sum that runs in O(1) time when self is
an Int range.