Question

I am profiling my code in php. Question is about next function:

// returns true if edge exists in the tree
protected function edgeExist( $srcNodeId, $firstToken ) {
    $result = array_key_exists( $srcNodeId, $this->edges )
              && array_key_exists( $firstToken, $this->edges[$srcNodeId]);
    return $result;
}

According to the profiler, function edgeExist consumes about 10% of running time, but function array_key_exists consumes about 0.2% of running time.
Why does function edgeExist consume so much?

Answer 1

This could be faster, try it:

protected function edgeExist( $srcNodeId, $firstToken ) {
    return isset($this->edges[$srcNodeId][$firstToken]);
}

There is a small difference when using array_key_exists() and isset(). Look in to the manual.