Python - Pandas - Unroll / Remove Cumulative Sum

Question

I have a data frame like the following (specific data below, this is generic). The no gives me a cumulative sum:

                 no
name day           
Jack         


        

Answer 1

Here's a method based on zip. It creates two series, the 2nd being offset by 1, and subtracts the difference between the two.

[n-nn for n,nn in zip(df['No'],df['No'][1:]+[0])]