src/Primitive/String/String.php
public function offsetExists($offset)
    {
        $length = $this->length();
        $offset = $this->getIntegerable($offset);

        if ($offset >= 0) return ($length > $offset);

        return ($length >= abs($offset));
    }
public function offsetExists($offset)
    {
        $length = $this->length();
        $offset = $this->getIntegerable($offset);

        if ($offset >= 0) return ($length > $offset);

        return ($length >= abs($offset));
    }
(PHP 5 &gt;= 5.0.0)
Whether a offset exists.
@link http://php.net/manual/en/arrayaccess.offsetexists.php
@param mixed $offset
An offset to check for.

@return boolean true on success or false on failure.
The return value will be casted to boolean if non-boolean was returned.