Pandas' secret mini-language

The DataFrame class (from Pandas) is a work of art. Even if you never "do data", priceless lessons can be gleaned by studying this class. It starts simple enough. Usually you will create a DataFrame by ingesting from a CSV file or database table or something. But you can whip up a small one like this: import pandas as pd df = pd . DataFrame ({ ' A ' : [ - 137 , 22 , - 3 , 4 , 5 ], ' B ' : [ 10 , 11 , 121 , 13 , 14 ], ' C ' : [ 3 , 6 , 91 , 12 , 15 ], }) This gives you a DataFrame with three colu