Definition
The key() function returns the element key from the current internal pointer position, returns false on error.
The key() function is commonly used along with the following functions:
-
current()– Returns the value of the current element in an array. -
next()– Moves the internal pointer of an array to the next element, and returns its value. -
prev()– Moves the internal pointer of an array to the previous element, and returns its value. -
end()– Moves the internal pointer of an array to its last element, and returns its value. -
reset()– Set the internal pointer of an array to its first element, and returns its value.
Syntax
key(array)
Parameters
| Parameter | Description |
|---|---|
array |
Required. Specifies the array to work on. |
Example
<?php
$cities = array("New York", "Salt Lake", "Tokyo");
echo key($cities);
echo "<br>";
// Examples in conjunction with other related functions
$ages = array("Mark" => 22, "Jeff" => 32, "Mike" => 28);
echo current($ages) . "<br>";
echo next($ages) . "<br>";
echo current($ages) . "<br>";
echo prev($ages) . "<br>";
echo end($ages) . "<br>";
echo prev($ages) . "<br>";
echo current($ages) . "<br>";
echo reset($ages) . "<br>";
echo next($ages) . "<br>";