title: Trying to multiply and make another row in Pandas Dataframe
body: <p>How do I make another row called 'Sum'), which contains the sum of for each order line (quantity, multiplied by price). in Pandas. Here is the code:</p>
  <pre><code>import pandas as pd
  from pathlib import Path
  
  #Make own path to file
  files = Path(&quot;&quot;).rglob(&quot;*.csv&quot;)
  
  df =[pd.read_csv(file,index_col=0) for file in files ] 
  
  df = pd.concat(df)
  
  df.reset_index(drop=True, inplace=True)
  
  df.dropna(subset = [&quot;Order ID&quot;], inplace=True)
  
  df['Price Each'].astype('int')
  df['Quantity Ordered'].astype('int')
  
  #df['Sum']= df['Quantity Ordered'].astype(int) * df['Price Each'].astype(int)
  
  df.assign('Sum'== df['Quantity Ordered'] * df['Price Each'])
  
  print(df)
  </code></pre>
  <p><a href="https://i.stack.imgur.com/hbpG6.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/hbpG6.png" alt="The DataFrame" /></a></p>
  <p>I get this back: ValueError: invalid literal for int() with base 10: '11.95'</p>
  <p>I have tried to use</p>
  <pre><code>df['Price Each'].astype('int')
  df['Quantity Ordered'].astype('int')
  df['Sum']= df['Quantity Ordered'].astype(int) * df['Price Each'].astype(int) 
  </code></pre>
  <p>But I got the same Error as before.
  Is there a way to to what i intend.</p>