title: PHP check if string contains space between words (not at beginning or end)
body: <p>I need to check if a string contains a space between words, but not at beginning or end. Let's say there are these strings:</p>
  
  <pre><code>1: "how r u ";
  2: "how r u";
  3: " howru";
  </code></pre>
  
  <p>Then only <code>2</code> should be true.  How could I do that?</p>