title: How to match ID numbers to merge two dataframes
body: <p>I have two dataframes both with columns that have ID numbers that should match.  However, the two dataframes do not have the same number of ID's. One has 118 IDs and one has 103 ID's. The dataframe that has 118 ID's has all 103 ID's though, but some extras.  I am wanting to take two columns from 118 row dataframe and merge them with the IDs that match in the 103 row dataframe based on ID number.  I dont know the easiest way to go about this problem.</p>