title: How to assign a new column that shows the total number of rows in a file
body: <p>Can anyone help? I want to assign a new column which counts how many rows do I have in a single file.
  Here I have file name in each row, you can see that the first 9 rows are in a single file(...block_10.jpg) so I want a new column that shows the total rows in the file.
  <a href="https://i.stack.imgur.com/Z7u41.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Z7u41.png" alt="Here is my dataframe" /></a></p>
  <p>I have extracted the values from the data frame using df.iloc</p>
  <pre><code>X = df.iloc[:,:-1].values # This is all the columns NOT including the last one
  Y = df.iloc[:,-1].values # This is the filename 
  </code></pre>