(PECL ds >= 1.0.0)
Ds\Sequence::find — Attempts to find a value's index
    Returns the index of the value, or FALSE if not found.
  
valueThe value to find.
    The index of the value, or FALSE if not found.
  
Note:
Values will be compared by value and by type.
Example #1 Ds\Sequence::find() example
<?php
$sequence = new \Ds\Vector(["a", 1, true]);
var_dump($sequence->find("a")); // 0
var_dump($sequence->find("b")); // false
var_dump($sequence->find("1")); // false
var_dump($sequence->find(1));   // 1
?>
以上例程的输出类似于:
int(0) bool(false) bool(false) int(1)