title: delete everything from List<string> with specific string
body: <p>i have:</p>
  
  <pre><code>List&lt;string&gt; MyFiles
  </code></pre>
  
  <p>i need to delete everything from this list that has a specific string inside of it</p>
  
  <p>for example if the list was:</p>
  
  <pre><code>alex1
  alex123
  alex234
  alex345
  </code></pre>
  
  <p>and i would like to delete every element in this list that has the string "1" in it? </p>