xtd::range Class Reference

Inheritance diagram for xtd::range:

Definition

Represents a range that has start and end indexes.

class range : public xtd::object, xtd::iequatable<range;

Header

#include <xtd/range>

Namespace

xtd

Library

xtd.core

Examples

The following example shows how to use xtd::range with a xtd::collections::generic::list.

#include <xtd/xtd>
 
auto main() -> int {
  auto items = list {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
  
  println("items[range::all()] = {}", items[range::all()]);
  println("items(range::start_at(2)) = {}", items(range::start_at(2)));
  println("items[range::start_at(index::from_end(8))] = {}", items[range::start_at(index::from_end(8))]);
  println("items(range::start_at(~8_i)) = {}", items(range::start_at(~8_i)));
  println("items[range::end_at(6)] = {}", items[range::end_at(6)]);
  println("items(range::end_at(index::from_start(6))) = {}", items(range::end_at(index::from_start(6))));
  println("items(range::end_at(~4_i)) = {}", items(range::end_at(~4_i)));
  println("items(range {{2, 6}}) = {}", items[range {2, 6}]);
  println("items[range {{3_i, ~2_i}}) = {}", items[range {3_i, ~2_i}]);
  println("items[{{0, 8}}] = {}", items[{0, 8}]);
  println("items[{{1_i, ~4_i}}][{{1_i, ~1_i}}] = {}", items[{1_i, ~4_i}][{1_i, ~1_i}]);
  println("items[{{1_i, ~4_i}}].where(_ % 2 == 0).select(_ * _) = {}", items[{1_i, ~4_i}].where(_ % 2 == 0).select(_ * _));
}
 
// This code produces the following output :
//
// items[range::all()] = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
// items(range::start_at(2)) = [3, 4, 5, 6, 7, 8, 9, 10]
// items[range::start_at(index::from_end(8))] = [3, 4, 5, 6, 7, 8, 9, 10]
// items(range::start_at(~8_i)) = [3, 4, 5, 6, 7, 8, 9, 10]
// items[range::end_at(6)] = [1, 2, 3, 4, 5, 6]
// items(range::end_at(index::from_start(6))) = [1, 2, 3, 4, 5, 6]
// items(range::end_at(~4_i)) = [1, 2, 3, 4, 5, 6]
// items(range {2, 6}) = [3, 4, 5, 6]
// items[range {3_i, ~2_i}) = [4, 5, 6, 7, 8]
// items[{0, 8}] = [1, 2, 3, 4, 5, 6, 7, 8]
// items[{1_i, ~4_i}][{1_i, ~1_i}] = [3, 4, 5]
// items[{1_i, ~4_i}].where(_ % 2 == 0).select(_ * _) = [4, 16, 36]

The following example shows how to use range literal operator.

#include <xtd/xtd>
 
auto main() -> int {
  auto items = list {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
  
  println(R"(items["0..10"_r] = {})", items["0..10"_r]);
  println(R"(items["2..6"_r] = {})", items["2..6"_r]);
  println(R"(items["0..~0"_r] = {})", items["0..~0"_r]);
  println(R"(items["2..~4"_r] = {})", items["2..~4"_r]);
  println(R"(items["~10..~0"_r] = {})", items["~10..~0"_r]);
  println(R"(items["~8..~4"_r] = {})", items["~8..~4"_r]);
}
 
// This code produces the following output :
//
// items["0..10"_r] = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
// items["2..6"_r] = [3, 4, 5, 6]
// items["0..~0"_r] = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
// items["2..~4"_r] = [3, 4, 5, 6]
// items["~10..~0"_r] = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
// items["~8..~4"_r] = [3, 4, 5, 6]

The following example shows how to create your own collection with xtd::range operator.

#include <xtd/xtd>
 
struct persona {
  string name;
  int age;
  
  auto to_string() const noexcept -> string {return string::format("persona {{{}, {}}}", name, age);}
};
 
class persona_collection {
public:
  persona_collection() = default;
  persona_collection(std::initializer_list<persona> items) : items_ {items} {}
  
  auto to_string() const noexcept -> string {return string::format("[{}]", string::join(", ", items_));}
  
  auto operator [](usize index) -> persona& {return items_[index];}
  auto operator [](usize index) const -> const persona& {return items_[index];}
  auto operator [](const xtd::range& range) -> span<persona> {return span<persona> {items_, range};}
  auto operator [](const xtd::range& range) const -> read_only_span<persona> {return read_only_span<persona> {items_, range};}
  
private:
  list<persona> items_;
};
 
auto main() -> int {
  auto items = persona_collection {{.name = "Oliver Queen", .age = 24}, {.name = "Laurel Lance", .age = 23}, {.name = "John \"Dig\" Diggle", .age = 27}, {.name = "Thea Queen", .age = 20}, {.name = "Felicity Smoak", .age = 22}};
  
  println("items = {}", items);
  
  println();
  println("items[range::all()] = {}", items[range::all()]);
  println("items[range {{2_i, ~0_i}}] = {}", items[range {2_i, ~0_i}]);
  println("items[range {{0, 4}}] = {}", items[range {0, 4}]);
  println(R"(items["1..3"_r] = {})", items["1..3"_r]);
}
 
// This code produces the following output :
//
// items = [persona {Oliver Queen, 24}, persona {Laurel Lance, 23}, persona {John "Dig" Diggle, 27}, persona {Thea Queen, 20}, persona {Felicity Smoak, 22}]
//
// items[range::all()] = [persona {Oliver Queen, 24}, persona {Laurel Lance, 23}, persona {John "Dig" Diggle, 27}, persona {Thea Queen, 20}, persona {Felicity Smoak, 22}]
// items[range {2_i, ~0_i}] = [persona {John "Dig" Diggle, 27}, persona {Thea Queen, 20}, persona {Felicity Smoak, 22}]
// items[range {0, 4}] = [persona {Oliver Queen, 24}, persona {Laurel Lance, 23}, persona {John "Dig" Diggle, 27}, persona {Thea Queen, 20}]
// items["1..3"_r] = [persona {Laurel Lance, 23}, persona {John "Dig" Diggle, 27}]

Classes
struct	offset_and_length
	Represents a offset and length. More...

Public Aliases
using	index_type
	Represents the xtd::range index type.
using	size_type
	Represents the size type.

Public Constructors
	range () noexcept=default
	Instantiates a new xtd::range instance.
	range (const index_type &start, const index_type &end) noexcept
	Instantiates a new xtd::range instance with the specified starting and ending indexes.
	range (xtd::integer auto start, const xtd::integer auto end) noexcept
	Instantiates a new xtd::range instance with the specified starting and ending indexes.

Public Properties
constexpr auto	end () const noexcept -> const index_type &
	Gets an Index that represents the exclusive end index of the range.
constexpr auto	start () const noexcept -> const index_type &
	Gets the inclusive start index of the Range.

Public Methods
auto	equals (const object &obj) const noexcept -> bool override
	Determines whether the specified object is equal to the current object.
auto	equals (const range &value) const noexcept -> bool override
	Indicates whether the current object is equal to another object of the same type.
auto	get_offset_and_length (size_type length) const -> offset_and_length
	Calculates the start offset and length of the range object using a collection length.
auto	get_hash_code () const noexcept -> size_type override
	Serves as a hash function for a particular type.
auto	to_string () const noexcept -> xtd::string override
	Returns the string representation of the current Range object.

Public Static Properties
static auto	all () noexcept -> xtd::range
	Gets a xtd::range object that starts from the first element to the end.

Public Static Methods
static auto	end_at (index_type end) noexcept -> xtd::range
	Creates a xtd::range object starting from the first element in the collection to a specified end index.
static auto	end_at (xtd::integer auto end) noexcept -> xtd::range
	Creates a xtd::range object starting from the first element in the collection to a specified end index.
static auto	parse (const xtd::string &value) -> xtd::range
	Converts the string to xtd::range equivalent.
static auto	start_at (index_type start) noexcept -> xtd::range
	Creates a new xtd::range object starting from a specified start index to the end of the collection.
static auto	start_at (xtd::integer auto start) noexcept -> xtd::range
	Creates a new xtd::range object starting from a specified start index to the end of the collection.
static auto	try_parse (const xtd::string &value, xtd::range &result) noexcept -> bool
	Converts the string to xtd::range equivalent. A return value indicates whether the conversion succeeded or failed.

Additional Inherited Members
	object ()=default
	Create a new instance of the ultimate base class object.
virtual auto	get_type () const noexcept -> type_object
	Gets the type of the current instance.
template<typename object_t>
auto	memberwise_clone () const -> xtd::unique_ptr_object< object_t >
	Creates a shallow copy of the current object.
template<typename object_a_t, typename object_b_t>
static auto	equals (const object_a_t &object_a, const object_b_t &object_b) noexcept -> bool
	Determines whether the specified object instances are considered equal.
template<typename object_a_t, typename object_b_t>
static auto	reference_equals (const object_a_t &object_a, const object_b_t &object_b) noexcept -> bool
	Determines whether the specified object instances are the same instance.

Member Typedef Documentation

index_type

using xtd::range::index_type

Represents the xtd::range index type.

size_type

using xtd::range::size_type

Represents the size type.

Constructor & Destructor Documentation

range() [1/3]

xtd::range::range ( )

defaultnoexcept

Instantiates a new xtd::range instance.

range() [2/3]

xtd::range::range ( const index_type & start, const index_type & end )

inlinenoexcept

Instantiates a new xtd::range instance with the specified starting and ending indexes.

Parameters

start	The inclusive start index of the range.
end	The exclusive end index of the range.

range() [3/3]

xtd::range::range ( xtd::integer auto start, const xtd::integer auto end )

inlinenoexcept

Instantiates a new xtd::range instance with the specified starting and ending indexes.

Parameters

start	The inclusive start index of the range.
end	The exclusive end index of the range.

Member Function Documentation

end()

auto xtd::range::end ( ) const -> const index_type &

inlinenodiscardconstexprnoexcept

Gets an Index that represents the exclusive end index of the range.

Returns

The end index of the range.

start()

auto xtd::range::start ( ) const -> const index_type &

inlinenodiscardconstexprnoexcept

Gets the inclusive start index of the Range.

Returns

The inclusive start index of the range.

equals() [1/2]

auto xtd::range::equals ( const object & obj ) const -> bool

inlinenodiscardoverridevirtualnoexcept

Determines whether the specified object is equal to the current object.

Parameters

obj	The object to compare with the current object.

Returns

true if the specified object is equal to the current object. otherwise, false.

Reimplemented from xtd::object.

equals() [2/2]

auto xtd::range::equals ( const range & value ) const -> bool

inlinenodiscardoverridevirtualnoexcept

Indicates whether the current object is equal to another object of the same type.

Parameters

obj	An object to compare with this object.

Returns

true if the current object is equal to the other parameter; otherwise, false.

Implements xtd::iequatable< range >.

get_offset_and_length()

auto xtd::range::get_offset_and_length ( size_type length ) const -> offset_and_length

inlinenodiscard

Calculates the start offset and length of the range object using a collection length.

Parameters

lengh

A positive integer that represents the length of the collection that the range will be used with.

Returns

The start offset and length of the range.

Examples

auto [start, length] = items_range.get_offset_and_length(items.size());

get_hash_code()

auto xtd::range::get_hash_code ( ) const -> size_type

inlinenodiscardoverridevirtualnoexcept

Serves as a hash function for a particular type.

Returns

A hash code for the current object.

Reimplemented from xtd::object.

to_string()

auto xtd::range::to_string ( ) const -> xtd::string

inlinenodiscardoverridevirtualnoexcept

Returns the string representation of the current Range object.

Returns

The string representation of the range.

Reimplemented from xtd::object.

all()

auto xtd::range::all ( ) -> xtd::range

inlinestaticnodiscardnoexcept

Gets a xtd::range object that starts from the first element to the end.

Returns

A range from the start to the end.

end_at() [1/2]

auto xtd::range::end_at ( index_type end ) -> xtd::range

inlinestaticnodiscardnoexcept

Creates a xtd::range object starting from the first element in the collection to a specified end index.

Parameters

end	The position of the last element up to which the Range object will be created.

Returns

A range that starts from the first element to end.

end_at() [2/2]

auto xtd::range::end_at ( xtd::integer auto end ) -> xtd::range

inlinestaticnodiscardnoexcept

Creates a xtd::range object starting from the first element in the collection to a specified end index.

Parameters

end	The position of the last element up to which the Range object will be created.

Returns

A range that starts from the first element to end.

parse()

auto xtd::range::parse ( const xtd::string & value ) -> xtd::range

inlinestaticnodiscard

Converts the string to xtd::range equivalent.

Parameters

value

A string containing a xtd::index to convert.

Returns

A xtd::range equivalent to the native value contained in value.

start_at() [1/2]

auto xtd::range::start_at ( index_type start ) -> xtd::range

inlinestaticnodiscardnoexcept

Creates a new xtd::range object starting from a specified start index to the end of the collection.

Parameters

start

The position of the first element from which the Range will be created.

Returns

A range from start to the end of the collection.

start_at() [2/2]

auto xtd::range::start_at ( xtd::integer auto start ) -> xtd::range

inlinestaticnodiscardnoexcept

Creates a new xtd::range object starting from a specified start index to the end of the collection.

Parameters

start

The position of the first element from which the Range will be created.

Returns

A range from start to the end of the collection.

try_parse()

auto xtd::range::try_parse ( const xtd::string & value, xtd::range & result ) -> bool

inlinestaticnodiscardnoexcept

Converts the string to xtd::range equivalent. A return value indicates whether the conversion succeeded or failed.

Parameters

value	A string containing a xtd::range to convert.
result	A xtd::range equivalent to the native value contained in value.

Returns

true if s was converted successfully; otherwise, false.

---

The documentation for this class was generated from the following file:

• xtd.core/include/xtd/range.hpp