If you enjoyed VLOOKUP…

I’ve always enjoyed VLOOKUP in Excel so it was with great joy that I learned some new methods in Pandas this week. So much more flexible & powerful – what a pleasure!


For example, you have a list of names in one series and a list of clothing sizes in a second series:

To map them:


Pandas looks up the value in s_names and tries to associate it with a corresponding index in s_sizes, returning the value from s_sizes if available.

The outcome:


Even more powerful – I highly recommend the help page which explains copious possible scenarios super-clearly! So let’s say I have a list of grandmothers and mothers, and a second list of mothers and children – I want to combine the 2 lists so that I end up with a complete list of all grandmothers, mothers and children:

To merge the lists:

master = pd.merge(senior, junior, how = "right")

The outcome:

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