[FIXED] Feature engineering, key error in python?

Issue

I am currently creating some additional features for my ML project. I created one feature (f1), insert it as a new column and want to use it now to calculate another feature, but I get a KeyError.

df['f1'] = df['column1'] - df['column2'] -->works fine

f1 has dtype: timedelta64, e.g. '0 days', '43 days'. Then I want to use this new column.

df['f2'] = df['f1'] + df ['column3'] --> Error occurs 

Errors:

KeyError Traceback (Most recent call last)
KeyError 'f1'

I don't know, what I can change to make it work. Thank you so much in advance.

Solution

Like the order you have written should works, if it gives error that f1 keys does not exist, maybe you are runing these lines in a notebook, and you are executing the second line before f1 created (like first line)

Answered By - amirhm