I have a dataframe as follows:

df = pd.DataFrame({'cost_saving': [10, 10, 20, 40, 60, 60],'id': ['a', 'b', 'c', 'd', 'e', 'f']})

How can I draw a cumulative chart of the savings?

I'm thinking of a line chart with number of items on the x-axis, and total savings on the y-axis.

The chart should show that the bulk of the savings come from a few items.

I've tried:

dftest['cost_saving'].plot(drawstyle='steps')

but it doesn't plot the cumulative values.

Thanks for any help!

I did:

df.set_index('id').cumsum()

And got:

    cost_saving
id             
a            10
b            20
c            40
d            80
e           140
f           200

This:

df.reset_index().plot.line(df.cost_saving.cumsum(), 'index', drawstyle='steps')

Gets me: