CODEWITHSUNDEEP
pythonpython-3.xpandasdataframe
user11321985
user11321985

Reputation:

Add Value based on condition in pandas

If Current value is > Previous Value (value.shift(-1)) Then add value to df[''].

Start from bottom to top. Please see my expecting dataframe to see what I'm trying to accomplish

Upvotes: 1

Views: 89

Answers (1)

ansev
ansev

Reputation: 30920

We can DataFrame.sort_values with groupby.cumsum checking condition with groupby.diff.

df2=df.sort_values('timestamp')
blocks=df2.groupby('id')['value'].diff(-1).ge(0).cumsum()
df['finalvalue']=df2['value'].mask(blocks.ne(0), 
                                   df2.groupby(['id',blocks])['value'].cumsum())
print(df)

            timestamp       id  value  finalvalue
0 2020-02-16 03:05:57  device1   1000        4100
1 2020-02-16 02:05:33  device1    900        3100
2 2020-02-16 01:05:08  device1    700        2200
3 2020-02-16 00:04:44  device1    300        1500
4 2020-02-15 23:04:19  device1   1200        1200
5 2020-02-15 22:03:55  device1    800         800
6 2020-02-15 21:03:29  device1    400         400
7 2020-02-15 20:03:04  device1    200         200
8 2020-02-15 19:02:39  device1    100         100
9 2020-02-15 18:02:14  device1      0           0

Upvotes: 1

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