Module ddash.algorithm.index

Returns an optional index of an element.

Example

import ddash.utils.optional: some, none;

auto arr1 = [1, 2, 3, 4];

assert(arr1.indexWhere!(a => a % 2 == 0) == some(1));
assert(arr1.lastIndexWhere!(a => a % 2 == 0) == some(3));

assert(arr1.indexWhere!(a => a == 5) == none);
assert(arr1.lastIndexWhere!(a => a % 2 == 0)(2) == some(1));

auto arr2 = [1, 2, 1, 2];

assert(arr2.indexOf(2) == some(1));

Functions

NameDescription
indexOf(range, value, fromIndex) Finds the first element in a range that equals some value
indexWhere(range, fromIndex) Returns optional index of the first element predicate returns true for.
lastIndexOf(range, value, fromIndex) Finds the first element in a range that equals some value
lastIndexWhere(range, fromIndex) Returns optional index of the last element predicate returns true for.