Output content based on the users input - php

Question

I am new to PHP and would like to display some information based on the users input; creating an unordered list on the website with their details.
I have the following scripts in my WordPress theme...
functions.php:
/* Add/remove author profile fields */
function new_contact_methods( $contactmethods ) {
unset($contactmethods['aim']);
unset($contactmethods['jabber']);
unset($contactmethods['yim']);
$contactmethods['google_plus'] = 'Google+';
$contactmethods['twitter'] = 'Twitter';
$contactmethods['facebook'] = 'Facebook';
$contactmethods['linkedin'] = 'Linkedin';
return $contactmethods;
}
add_filter('user_contactmethods','new_contact_methods', 10, 1);
single.php:
<ul style="margin: 0;">
<li></li>
<li></li>
<li></li>
<li></li>
<li></li>
</ul>
How would I output the information from the users profile settings:
Only if they have placed content into any of the fields above.
For example, I don't wish to display an unordered list or list items which haven't been place into any of the fields:
https://plus.google.com/example
http://au.linkedin.com/in/example
thanks.

Answer 1

Using the_author_meta() will echo out the value, so you can't really check it ahead of time unless you buffer the output or something. Instead you can use get_the_author_meta. The difference is that instead of echoing the value, it just returns it. So you can look at the value, then use php's empty to see if it has been filled in, so your code might look like this
<ul style="margin: 0;">
<?php
$url=get_the_author_meta('url');
if (!empty($url))
{
?>
<li><a href="<?php the_author_meta('url'); ?>" target="_blank">
<?php the_author_meta('url'); ?></a>
</li>
<?php
}
//...
and a quick way to grab all the properties you want
<?php
$metaInfo=array('url','twitter','google_plus','facebook','linkedin');
$validProperties=0;
foreach($metaInfo as $infoItem)
{
$itemValue=get_the_author_meta($infoItem);
if (!empty($itemValue))
{
$validProperties++; //increments by 1
}
}
?>
<?php
if ($validProperties > 0)
{ //meaning we found at least 1
?>
<ul style="margin: 0;">
<?php
foreach($metaInfo as $infoItem)
{
$itemValue=get_the_author_meta($infoItem);
if (!empty($itemValue))
{
?>
<li>
<a href="<?php the_author_meta($infoItem); ?>" target="_blank">
<?php the_author_meta($infoItem); ?></a>
</li>
<?php
}
}
?>
</ul>
<?php
}
else
{
//else we found none so display nothing! or do something like
echo "no data found!";
}
?>