Comparison of Pandas lookup times

Question

After experimenting with timing various types of lookups on a Pandas (0.17.1) DataFrame I am left with a few questions.

Here is the set up...

import pan         


        

Answer 1

(1) pandas currently has no knowledge of the sortedness of a column.
If you want to take advantage of sorted data, you could use df2.letter.searchsorted See @unutbu's answer for an explanation of what's actually causing the difference in time here.

(2) The hash table that sits underneath the index is lazily created, then cached.