How to do rolling subtraction repeatedly with a Pandas Dataframe?
I have a dataframe that looks like this:
value
100
1
4
10
5
3
I want to repeatedly subtract previous value with current value. I want the following output:
100
99
95
85
80
77
How can I do this? If I have multiple columns in the dataframe, how can I apply the same operation to all of the columns?
A vectorized solution:
-(df['value']).cumsum() + df['value'].iat[0]*2
Output:
0 100
1 99
2 95
3 85
4 80
5 77
Name: value, dtype: int64
Combine expanding with np.subtract.reduce:
df.value.expanding(1).agg(np.subtract.reduce)
0 100.0
1 99.0
2 95.0
3 85.0
4 80.0
5 77.0
Name: value, dtype: float64