phobos ~master (2024-10-15T22:24:56Z)

countUntil

std algorithm searching

Counts elements in the given input range until the given predicate is true for one of the elements of haystack.

  1. auto countUntil(R haystack, Rs needles)
  2. ptrdiff_t countUntil(R haystack, N needle)
  3. ptrdiff_t countUntil(R haystack)
    ptrdiff_t
    countUntil
    (
    alias pred
    R
    )
    (
    R haystack
    )
    if (
    isInputRange!R &&
    is(typeof(unaryFun!pred(haystack.front)) : bool)
    )

Parameters

pred

Unary predicate for determining when to stop counting.

haystack R

The input range to be counted.

Return Value

Type: ptrdiff_t

- The number of elements which must be popped from the front of haystack before reaching an element for which startsWith!pred(haystack) is true. - If startsWith!pred(haystack) is not true for any element in haystack, then -1 is returned.

Examples

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);

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std algorithm searching aliasesfunctionsstructstemplates

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