View source code
Display the source code in std/range/package.d from which this page was generated on github.
Report a bug
If you spot a problem with this page, click here to create a Bugzilla issue.
Improve this page
Quickly fork, edit online, and submit a pull request for this page. Requires a signed-in GitHub account. This works well for small changes. If you'd like to make larger changes you may want to consider using local clone.

std.range.takeNone - multiple declarations

Function takeNone

Returns an empty range which is statically known to be empty and is guaranteed to have length and be random access regardless of R's capabilities.

auto takeNone(R)()
if (isInputRange!R);


auto range = takeNone!(int[])();
writeln(range.length); // 0

Function takeNone

Creates an empty range from the given range in Ο(1). If it can, it will return the same range type. If not, it will return takeExactly(range, 0).

auto takeNone(R) (
  R range
if (isInputRange!R);


import std.algorithm.iteration : filter;
assert(takeNone([42, 27, 19]).empty);
assert(takeNone(filter!"true"([42, 27, 19])).empty);


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


Boost License 1.0.