php returning mixed data types - good or bad
<p>When returnign values in php is it considered good or bad practivce to return mixed data types.  Im working on a project where i am constantly being faced with methods that wither return and id number or null.  Im handling the null value by checking for null and returning -1 if is null.</p>

<p>Another situation where i find myself in a lot is where a method should do something and return a string.  But sometimes its not possible to return the string as it wasnt found or an exception happened.  Whats best to do here?  return a string like 'failed' or something.  This then creates a string coupling between methods i think as the calling method has to know exactly the string failure message to check for??</p>

<p>EDIT:  OK there are a few different opinions already.  I like the idea of returning false on failure and the actual result whatever its data type be on success.  But... is there a defacto best practice when it comes to this?  I mean, what do programmers in otger languages do i.e. java and c++ etc in these situations?</p>
