title: How to append a column from one csv file to second csv (with different indices)
body: <p>I am working on concatenating many csv files together and want to take one column, from a multicolumn csv, and append it as a new column in a second csv. The problem is that the columns have different numbers of rows so the new column that I am adding to the existing csv gets cut short once the row index from the existing csv is reached. </p>
  
  <p>I have tried to read in the new column as a second dataframe and then add that dataframe as a new column to the existing csv.</p>
  
  <pre><code>df = pd.read_csv("Existing CSV.csv")
  df2 = pd.read_csv("New CSV.csv", usecols = ['Desired Column'])
  df["New CSV"] = df2
  </code></pre>
  
  <p>"Existing CSV" has 1200 rows of data while "New CSV" has 1500 rows. When I run the code, the 'New CSV" column is added to "Existing CSV", however, only the first 1200 rows of data are included. </p>
  
  <p>Ideally, all 1500 rows from "New CSV" will be included and the 300 rows missing from "Existing CSV" will be left blank.</p>