Google Analytics snippet in functions.php

wp-analytics.php

<?php
//include GA tracking code before the closing head tag
add_action('wp_head', 'google_analytics_tracking_code');

function google_analytics_tracking_code() { ?>
    <!-- Google Analytics -->
    <script>
        (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
                (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
            m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
        })(window,document,'script','//www.google-analytics.com/analytics.js','ga');

        ga('create', 'UA-xxxxxxx-1', 'auto');
        ga('send', 'pageview');
    </script>
<?php } ?>