Get Distance Between Two Points

from math import sqrt

def get_distance(origin, destination):
    '''Distance Between Two Points'''
    (o_x, o_y) = origin
    (d_x, d_y) = destination
    return sqrt((d_x - o_x)**2.0 + (d_y - o_y)**2.0)

Synchronize $remote and $local Files

function sync_files( $remote, $local )
{
    if ( ! is_file( $local ) ) { return copy( $remote, $local ); }

    $handle = fopen( $remote, 'r' );
    if ( ! $handle ) { die( "Could not open {$remote}." ); }
    $meta = stream_get_meta_data( $handle );
    fclose( $handle );

    foreach( $meta['wrapper_data'] as $response )
    {
        // Redirection
        if ( substr( strtolower( $response ), 0, 10 ) === 'location: ' ) {
            return sync_files( substr( $response, 10 ), $local );
        }

        // Compare sizes
        if ( substr( strtolower( $response ), 0, 16 ) === 'content-length: ' )
        {
            if ( (int) filesize( $local ) !== (int) substr( $response, 16 ) ) {
                return copy( $remote, $local );
            }
            continue;
        }

        // Compare dates
        if ( substr( strtolower( $response ), 0, 15 ) === 'last-modified: ' )
        {
            if ( (int) filemtime( $local ) < (int) strtotime( substr( $response, 15 ) ) ) {
                return copy( $remote, $local );
            }
            continue;
        }
    }

    return false;
}

Remove Nodes (Comments, Script Tags) from $html String

function remove_nodes( $html, array $selectors = array( '//comment()', '//script' ) )
{
    $dom = new DOMDocument;
    $dom->loadHtml( strval( $html ) );
    $dom->preserveWhiteSpace = false;
    $dom->formatOutput = true;
    $xpath = new DOMXPath( $dom );
    foreach( $selectors as $selector ) {
        while ( $node = $xpath->query( $selector )->item( 0 ) ) {
            // Remove selected tag from html string
            $node->parentNode->removeChild( $node );
        }
    }
    return $dom->saveHTML();
}

Sanitize Key : Lowercase Accentless $string, Special Characters $replacement

function sanitize_key( $string, $replacement = '_' )
{
    // Lowercase and remove accents
    $string = htmlentities( trim( strtolower( strval( $string ) ) ), ENT_NOQUOTES );
    $string = preg_replace( '/&([a-z])(?:acute|cedil|caron|circ|grave|orn|ring|slash|th|tilde|uml);/', '$1', $string );
    $string = preg_replace( '/&([a-z]{2})(?:lig);/', '$1', $string );
    $string = preg_replace( '/&[^;]+;/', $replacement, $string );
    // Replace non-alphanumeric characters
    return preg_replace( '/[^a-z0-9]+/', $replacement, $string );
}