title: How do I target a specific day of the current month with DateTime::modify?
body: <p>I need to be able to set a DateTime object to a certain day of the current month. I can obviously do this by getting the current month and creating a new DateTime, or checking the current day and creating a DateInterval object to modify the DateTime, but I want to just give plain text arguments to DateTime::modify.</p>
  
  <p>I'm looking for something like:</p>
  
  <pre><code>$datetime-&gt;modify('10th day this month');
  </code></pre>
  
  <p>but this gives me an error like</p>
  
  <blockquote>
    <p>PHP Warning:  DateTime::modify(): Failed to parse time string (10th day this month) at position 0 (1): Unexpected character in php shell code on line 1</p>
  </blockquote>
  
  <p>and I don't seem able to find the correct construction of the sentence to make PHP play nicely.</p>