Getting last 5 elements of a php array

Question

How can I get the last 5 elements of a PHP array?

My array is dynamically generated by a MySQL query result. The length is not fixed. If the length is smaller or equ

Answer 1

I just want to extend the question a little bit. What if you looping though a big file and want to keep the last 5 lines or 5 elements from a current position. And you don't want to keep huge array in a memory and having problems with the performance of array_slice.

This is a class that implements ArrayAccess interface.

It gets array and desired buffer limit.

You can work with the class object like it's an array but it will automatically keep ONLY last 5 elements

container = $myArray;
        $this->limit = $limit;
    }
    public function offsetSet($offset, $value) {
        if (is_null($offset)) {
            $this->container[] = $value;
        } else {
            $this->container[$offset] = $value;
        }
        $this->adjust();
    }

    public function offsetExists($offset) {
        return isset($this->container[$offset]);
    }

    public function offsetUnset($offset) {
        unset($this->container[$offset]);
    }

    public function offsetGet($offset) {
        return isset($this->container[$offset]) ? $this->container[$offset] : null;
    }
    public function __get($offset){
        return isset($this->container[$offset]) ? $this->container[$offset] : null;
    }
    private function adjust(){
        if(count($this->container) == $this->limit+1){
            $this->container = array_slice($this->container, 1,$this->limit);
        }
    }
}


$buf = new MyBuffer();
$buf[]=1;
$buf[]=2;
$buf[]=3;
$buf[]=4;
$buf[]=5;
$buf[]=6;

echo print_r($buf, true);

$buf[]=7;
echo print_r($buf, true);


echo "\n";
echo $buf[4];