Suppose I have a pandas table like this:
A B
1 1
1 5
1 2
2 3
2 2
2 1
I would like to create order column B by increasing value by the group in A - but also create a third column C whereby this is the cumulative sum of B by group in A, viz:
A B C
1 1 1
1 2 3
1 5 8
2 1 1
2 2 3
2 3 6
I'm assuming the first part of getting the column ascending can be covered off by the code below, but unsure about the 2nd step of the cumulative sum of B in a new column C. Thanks in advance...!
df = df.sort_values(['B'],ascending=True).groupby('A')
