extract hour from timestamp with python

问题:

I have a dataframe df_energy2

df_energy2.info()
<class 'pandas.core.frame.DataFrame'>
RangeIndex: 29974 entries, 0 to 29973
Data columns (total 4 columns):
TIMESTAMP        29974 non-null datetime64[ns]
P_ACT_KW         29974 non-null int64
PERIODE_TARIF    29974 non-null object
P_SOUSCR         29974 non-null int64
dtypes: datetime64[ns](1), int64(2), object(1)
memory usage: 936.8+ KB

with this structure :

df_energy2.head()

TIMESTAMP P_ACT_KW PERIODE_TARIF P_SOUSCR
2016-01-01 00:00:00 116 HC 250 
2016-01-01 00:10:00 121 HC 250

Is there any python fucntion which can extract hour from TIMESTAMP?

Kind regards

回答1:

I think you need dt.hour:

print (df.TIMESTAMP.dt.hour)
0    0
1    0
Name: TIMESTAMP, dtype: int64

df['hours'] = df.TIMESTAMP.dt.hour
print (df)
            TIMESTAMP  P_ACT_KW PERIODE_TARIF  P_SOUSCR  hours
0 2016-01-01 00:00:00       116            HC       250      0
1 2016-01-01 00:10:00       121            HC       250      0

回答2:

Given your data:

df_energy2.head()

TIMESTAMP P_ACT_KW PERIODE_TARIF P_SOUSCR
2016-01-01 00:00:00 116 HC 250 
2016-01-01 00:10:00 121 HC 250

You have timestamp as the index. For extracting hours from timestamp where you have it as the index of the dataframe:

  hours = df_energy2.index.hour

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Edit: Yes, jezrael you're right. Putting what he has stated: pandas dataframe has a property for this i.e. dt :

<dataframe>.<ts_column>.dt.hour

Example in your context - the column with date is TIMESTAMP

df.TIMESTAMP.dt.hour

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