Partition pandas .diff() in multi-index level

Question

My question relates to calling .diff() within the partition of a multi index level

In the following sample the output of the first

df.diff() is

<         


        

Answer 1

Just groupby by level=0 or 'Greek' if you prefer and then you can call diff on values:

In [179]:

df.groupby(level=0)['values'].diff()
Out[179]:
Greek  English
alpha  a         NaN
       b           2
       c           2
       d           2
beta   e         NaN
       f           1
       g           1
       h           1
dtype: float64