title: How to check in every row in a column if it contains a substring
body: <p>Let's say I have a column 'name' in the dataframe <code>df</code>:</p>
  
  <pre><code>apple
  apple123
  app
  be
  aple
  </code></pre>
  
  <p>and, I want to check if every row in the <code>name</code> column contains the word <code>apple</code>.
  The way I did it was to use <code>grepl</code>, <code>grepl('apple',df$name)</code>, I was hoping it would return <code>'TRUE','TRUE','FALSE','FALSE','FALSE'</code>, however, it returned 5 <code>'FALSE'</code> instead.</p>
  
  <p>Did I do anything wrong here, if not <code>grep</code>l, what function should I use?</p>