index_of

fn index_of(Vec<int> xs, int needle) -> int

fn index_of(Vec<string> xs, string needle) -> int

use collections::vec::{index_of};

Returns the index of the first needle in xs, or -1. There is an int and a string version.

fn index_of(Vec<int> xs, int needle) -> int#

Parameters#

Returns#

int

Contracts#

Checked according to --contracts (see Contracts).

ensures result >= -1 && result < xs.len()
ensures result < 0 || xs[result] == needle

fn index_of(Vec<string> xs, string needle) -> int#

Returns the index of the first needle in xs, or -1.

Parameters#

Returns#

int

Contracts#

Checked according to --contracts (see Contracts).

ensures result >= -1 && result < xs.len()
ensures result < 0 || xs[result] == needle

Examples#

use collections::vec::{index_of};
use tests::assert;
let xs: Vec<int> = [3, 1, 4, 1];
assert!(index_of(xs, 1) == 1);
assert!(index_of(xs, 9) == -1);

See also#

• int
• string
• fold_int: The same as fold; kept for older code.
• contains: Returns true when needle is in xs.
• binary_search: Finds needle in the ascending vector xs by halving, and returns an index holding it.
• dedup: Returns xs with runs of equal neighbours collapsed to one value.
• map: Returns a new vector with mapper applied to each element, in order.
• filter: Returns the elements for which pred is true, in order.