The D Programming Language's Unofficial Docs
beta
The D Programming Language's Unofficial Docs
beta
Compares two ranges for equality. The ranges may have different element types, as long as pred(r1.front, r2.front) evaluates to bool. Performs O(min(r1.length, r2.length)) evaluations of pred.
1 import std.algorithm.comparison : equal; 2 import std.math : approxEqual; 3 4 int[4] a = [ 1, 2, 4, 3 ]; 5 assert(!equal(a[], a[1..$])); 6 assert(equal(a[], a[])); 7 assert(equal!((a, b) => a == b)(a[], a[])); 8 9 // different types 10 double[4] b = [ 1.0, 2, 4, 3]; 11 assert(!equal(a[], b[1..$])); 12 assert(equal(a[], b[])); 13 14 // predicated: ensure that two vectors are approximately equal 15 double[4] c = [ 1.005, 2, 4, 3]; 16 assert(equal!approxEqual(b[], c[]));
Tip: equal can itself be used as a predicate to other functions. This can be very useful when the element type of a range is itself a range. In particular, equal can be its own predicate, allowing range of range (of range...) comparisons.
import std.algorithm.comparison : equal; import std.range : iota, chunks; assert(equal!(equal!equal)( [[[0, 1], [2, 3]], [[4, 5], [6, 7]]], iota(0, 8).chunks(2).chunks(2) ));
Compares two ranges for equality, as defined by predicate pred (which is == by default).