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Function std.array.overlap

Returns the overlapping portion, if any, of two arrays. Unlike equal, overlap only compares the pointers and lengths in the ranges, not the values referred by them. If r1 and r2 have an overlapping slice, returns that slice. Otherwise, returns the null slice.

CommonType!(T[],U[]) overlap(T, U) (
  T[] a,
  U[] b
) @trusted
if (is(typeof(a.ptr < b.ptr) == bool));


a The first array to compare
b The second array to compare


The overlapping portion of the two arrays.


int[] a = [ 10, 11, 12, 13, 14 ];
int[] b = a[1 .. 3];
writeln(overlap(a, b)); // [11, 12]
b = b.dup;
// overlap disappears even though the content is the same
assert(overlap(a, b).empty);

static test()() @nogc
    auto a = "It's three o'clock"d;
    auto b = a[5 .. 10];
    return b.overlap(a);

//works at compile-time
static assert(test == "three"d);


Andrei Alexandrescu and Jonathan M Davis


Boost License 1.0.