Take

Lazily takes only up to n elements of a range. This is particularly useful when using with infinite ranges.

Unlike takeExactly, take does not require that there are n or more elements in input. As a consequence, length information is not applied to the result unless input also has length information.

struct Take(Range)
struct Take (
Range
) if (
isInputRange!(Unqual!Range) &&
!(
(
!isInfinite!(Unqual!Range) &&
hasSlicing!(Unqual!Range)
) ||
is(Range T == Take!T)
)
) {
R source;
bool empty [@property getter];
auto ref front [@property getter];
void popFront();
static if(isForwardRange!R)

Take save [@property getter];
static if(hasAssignableElements!R)

ElementType!R front [@property setter];
static if(hasMobileElements!R)

auto moveFront();
static if(isInfinite!R)

size_t length [@property getter];
alias opDollar = length;
static if(isInfinite!R)

auto opSlice(size_t i, size_t j);
static if(!(isInfinite!R))
static if(hasLength!R)

size_t length [@property getter];
static if(isRandomAccessRange!R)

void popBack();
static if(isRandomAccessRange!R)

auto ref back [@property getter];
static if(isRandomAccessRange!R)

auto ref opIndex(size_t index);
static if(isRandomAccessRange!R)
static if(hasAssignableElements!R)

ElementType!R back [@property setter];
static if(isRandomAccessRange!R)
static if(hasAssignableElements!R)

void opIndexAssign(ElementType!R v, size_t index);
static if(isRandomAccessRange!R)
static if(hasMobileElements!R)

auto moveBack();
static if(isRandomAccessRange!R)
static if(hasMobileElements!R)

auto moveAt(size_t index);
size_t maxLength [@property getter];
}
template Take(R)

Members

Aliases

opDollar alias opDollar = length
moveAt auto moveAt(size_t index)
moveBack auto moveBack()
moveFront auto moveFront()
opIndex auto ref opIndex(size_t index)
opIndexAssign void opIndexAssign(ElementType!R v, size_t index)
opSlice auto opSlice(size_t i, size_t j)
popBack void popBack()
popFront void popFront()
back auto ref back [@property getter]
ElementType!R back [@property setter]: Range primitives

Functions

Properties

empty bool empty [@property getter]
front auto ref front [@property getter]
ElementType!R front [@property setter]
length size_t length [@property getter]: Range primitives
maxLength size_t maxLength [@property getter]: Access to maximal length of the range. Note: the actual length of the range depends on the underlying range. If it has fewer elements, it will stop before maxLength is reached.
save Take save [@property getter]: Range primitives

Variables

source R source;: User accessible in read and write

Return Value

At minimum, an input range. If the range offers random access and length, take offers them as well.

Examples

import std.algorithm.comparison : equal;

int[] arr1 = [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ];
auto s = take(arr1, 5);
assert(s.length == 5);
assert(s[4] == 5);
assert(equal(s, [ 1, 2, 3, 4, 5 ][]));

If the range runs out before n elements, take simply returns the entire range (unlike takeExactly, which will cause an assertion failure if the range ends prematurely):

import std.algorithm.comparison : equal;

int[] arr2 = [ 1, 2, 3 ];
auto t = take(arr2, 5);
assert(t.length == 3);
assert(equal(t, [ 1, 2, 3 ]));

The OpenD Programming Language