title: pandas: subtracting two columns and saving result as an absolute
body: <p>I have the code where I have a csv file opened in pandas and a new one I'm creating. There's a row I need to create "two last lines commented out" of an absolute value of subtracting two rows. I've tried a number of ideas in my head all bring an error.</p>
  
  <pre><code>import pandas as pd
  import numpy as np
  
  df = pd.read_csv(filename_read)
  ids = df['id']
  
  oosDF = pd.DataFrame()
  oosDF['id'] = ids
  oosDF['pred'] = pred
  oosDF['y'] = df['target']
  #oosDF['diff'] = oosdF['pred'] - oosDF['y']
  #oosDF['diff'] = oosDF.abs()
  </code></pre>