Create a column which increments value for changes in another row

Question

I have a dataframe with two columns as below:

Var1Var2
a   28
b   28
d   28
f   29
f   29
e   30
b   30
m   30
l   30
u   31
t   31
t   31

I\'d

Answer 1

Using category

df.Var2.astype('category').cat.codes.add(1)
Out[525]: 
0     1
1     1
2     1
3     2
4     2
5     3
6     3
7     3
8     3
9     4
10    4
11    4
dtype: int8

Updated

from itertools import groupby
grouped = [list(g) for k, g in groupby(df.Var2.tolist())]
np.repeat(range(len(grouped)),[len(x) for x in grouped])+1