I have a df1:
ID Date
23 4/5/2011
12 4/7/2012
14 6/17/2020
90 12/20/1994
Currently these columns are both character classes. I would like to create a third column that merges these two columns with an underscore. The output would look like:
ID Date Identifier
23 4/5/2011 23_4/5/2011
12 4/7/2012 12_4/7/2012
14 6/17/2020 14_6/17/2020
90 12/20/1994 90_12/20/1994