🎯 Optionals, Error Unions, Enums, and switch

Return the index of the first element equal to target, or null if not found.

Zig's optional type ?T represents "either a value of type T or null":

fn find(x: i32) ?usize {
    return null;   // not found
    return 3;      // found at index 3
}

`items`	`target`	result	why
`[10, 20, 30, 40]`	`30`	`2`	found at index 2
`[1, 2, 1, 2]`	`2`	`1`	the first match wins, not the later one
`[1, 2, 3]`	`5`	`null`	no element equals the target
`[]`	`1`	`null`	nothing to search

Loop with for (items, 0..) |item, i| and return i when item == target.

Zig

/// Return the index of the first occurrence of target, or null
fn findFirst(items: []const i32, target: i32) ?usize {
    for (items, 0..) |item, i| {
        if (item == target) return i;
    }
    return null;
}

Find First Match

Safe Divide