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
Range
using the given beginning and end.
Instance Method Summary
- #==(other : Range)
-
#===(value)
Same as
#includes?
, useful for thecase
expression. -
#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
Iterator
that 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
Iterator
over the elements of this range. -
#end : E
Returns the object that defines the end of the range.
-
#excludes_end? : Bool
Returns
true
if this range excludes the end element. -
#exclusive? : Bool
Returns
true
if the range is exclusive. -
#includes?(value) : Bool
Returns
true
if 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
Array
with 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
Iterator
over the elements of this range. -
#sample(random : Random = Random::DEFAULT)
Optimized version of
Enumerable#sample
that runs in O(1) time whenself
is anInt
orFloat
range. -
#sample(n : Int, random = Random::DEFAULT)
:inherit:
-
#size
Returns the number of values in this range.
- #step(by = 1, &) : Nil
- #step(by = 1) : Iterator
-
#sum(initial)
Optimized version of
Enumerable#sum
that runs in O(1) time whenself
is anInt
range. -
#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!, 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
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 the range is exclusive.
Returns false
otherwise (default).
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 Int
s, runs in constant
time instead of linear.
(3..8).size # => 6
(3...8).size # => 5
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.