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std.range.take - multiple declarations

Function take

Lazily takes only up to n elements of a range. This is particularly useful when using with infinite ranges. If the range offers random access and length, Take offers them as well.

Prototype

Take!R take(R)(
  R input,
  size_t n
)
if (isInputRange!(Unqual!R) && !isInfinite!(Unqual!R) && hasSlicing!(Unqual!R) && !is(R T == Take!T));

Example

import std.algorithm : 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 ][]));

Example

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 : equal;

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

Struct Take

Lazily takes only up to n elements of a range. This is particularly useful when using with infinite ranges. If the range offers random access and length, Take offers them as well.

Example

import std.algorithm : 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 ][]));

Example

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 : equal;

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

Authors

Andrei Alexandrescu, David Simcha, and Jonathan M Davis. Credit for some of the ideas in building this module goes to Leonardo Maffi.

License

Boost License 1.0.

Comments