preg_match vs parse_url

<?php

$url1 = '//google.com';
$url2 = 'http://google.com';
$url3 = 'https://google.com';
$url4 = 'google.com';
$email = '[email protected]';

if( 1 === preg_match( '|^https?://|', $url1 ) ){
    echo "url1 preg_matched\n";
}

if( 1 === preg_match( '|^https?://|', $url2 ) ){
    echo "url2 preg_matched\n";
}

if( 1 === preg_match( '|^https?://|', $url3 ) ){
    echo "url3 preg_matched\n";
}

if( 1 === preg_match( '|^https?://|', $url4 ) ){
    echo "url4 preg_matched\n";
}

if( 1 === preg_match( '|^https?://|', $email ) ){
    echo "email preg_matched\n";
}

echo "url1: "; var_dump( parse_url( $url1 ) );

echo "url2: "; var_dump( parse_url( $url2 ) );

echo "url3: "; var_dump( parse_url( $url3 ) );

echo "url4: "; var_dump( parse_url( $url4 ) );

echo "email: "; var_dump( parse_url( $email ) );