The predicate for determining when to stop counting.
The input range to be counted.
The number of elements which must be popped from the front of haystack before reaching an element for which startsWith!pred(haystack, needles) is true. If startsWith!pred(haystack, needles) is not true for any element in haystack, then -1 is returned. If more than one needle is provided, countUntil will wrap the result in a tuple similar to Tuple!(ptrdiff_t, "steps", ptrdiff_t needle)
assert(countUntil("hello world", "world") == 6); assert(countUntil("hello world", 'r') == 8); assert(countUntil("hello world", "programming") == -1); assert(countUntil("日本語", "本語") == 1); assert(countUntil("日本語", '語') == 2); assert(countUntil("日本語", "五") == -1); assert(countUntil("日本語", '五') == -1); assert(countUntil([0, 7, 12, 22, 9], [12, 22]) == 2); assert(countUntil([0, 7, 12, 22, 9], 9) == 4); assert(countUntil!"a > b"([0, 7, 12, 22, 9], 20) == 3); // supports multiple needles auto res = "...hello".countUntil("ha", "he"); assert(res.steps == 3); assert(res.needle == 1); // returns -1 if no needle was found res = "hello".countUntil("ha", "hu"); assert(res.steps == -1); assert(res.needle == -1);
import std.ascii : isDigit; import std.uni : isWhite; assert(countUntil!(isWhite)("hello world") == 5); assert(countUntil!(isDigit)("hello world") == -1); assert(countUntil!"a > 20"([0, 7, 12, 22, 9]) == 3);
Counts elements in the given forward range until the given predicate is true for one of the given needles.