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Function `std.range.radial`

Iterates a random-access range starting from a given point and progressively extending left and right from that point. If no initial point is given, iteration starts from the middle of the range. Iteration spans the entire range.


						
				auto radial(Range, I)
				(
				

				  Range r,
				

				  I startingIndex
				

				)
				

				if (isRandomAccessRange!(Unqual!Range) && hasLength!(Unqual!Range) && hasSlicing!(Unqual!Range) && isIntegral!I);
				

				

				auto radial(R)
				(
				

				  R r
				

				)
				

				if (isRandomAccessRange!(Unqual!R) && hasLength!(Unqual!R) && hasSlicing!(Unqual!R));

When startingIndex is 0 the range will be fully iterated in order and in reverse order when r.length is given.

Parameters

Name	Description
r	a random access range with length and slicing
startingIndex	the index to begin iteration from

Returns

A forward range with length

Example

import std.algorithm.comparison : equal;
int[] a = [ 1, 2, 3, 4, 5 ];
assert(equal(radial(a), [ 3, 4, 2, 5, 1 ]));
a = [ 1, 2, 3, 4 ];
assert(equal(radial(a), [ 2, 3, 1, 4 ]));

// If the left end is reached first, the remaining elements on the right
// are concatenated in order:
a = [ 0, 1, 2, 3, 4, 5 ];
assert(equal(radial(a, 1), [ 1, 2, 0, 3, 4, 5 ]));

// If the right end is reached first, the remaining elements on the left
// are concatenated in reverse order:
assert(equal(radial(a, 4), [ 4, 5, 3, 2, 1, 0 ]));

Authors

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

License

Boost License 1.0.