CODEWITHSUNDEEP
pythonpandasdataframegroup-by
user3318023
user3318023

Reputation: 473

Calculate changes of column in Pandas

I have a dataframe with data and I want calculate changes of values during time.

UserId DateTime Value
     1        1     0
     1        2     0
     1        3     0
     1        4     1
     1        6     1
     1        7     1
     2        1     0
     2        2     1
     2        3     1
     2        4     0
     2        6     1
     2        7     1

So after script execution I want to get a column with change identifier (for user and date). Only changes from 0 to 1 is interesting.

UserId DateTime Value  IsChanged
     1        1     0         0
     1        2     0         0
     1        3     0         0 
     1        4     1         1  <- Value was changed from 0 to 1
     1        6     1         0
     1        7     1         0
     2        1     0         0
     2        2     1         1 <- Value was changed from 0 to 1
     2        3     1         0
     2        4     0         0 <- Change from 1 to 0 not interesting
     2        6     1         1 <- Value was changed from 0 to 1 for the user
     2        7     1         0

Upvotes: 1

Views: 1123

Answers (1)

FLab
FLab

Reputation: 7476

What about this?

# df is your dataframe    
df['IsChanged'] =  (df['Value'].diff()==1).astype(int)

The only case you care about is Value being 0 before and 1 after, so you can simply calculate the change in value and check if it is equal to 1.

    UserId  DateTime  Value  IsChanged
0        1         1      0          0
1        1         2      0          0
2        1         3      0          0
3        1         4      1          1
4        1         6      1          0
5        1         7      1          0
6        2         1      0          0
7        2         2      1          1
8        2         3      1          0
9        2         4      0          0
10       2         6      1          1
11       2         7      1          0

Upvotes: 1

Related Questions