Never figured this one out.
A datetime index in a dataframe is selected by df.loc['2022-07-18 15:15:00'] or iloc or whatever but how can I perform a conditional check on the time in an datetime to create a column value for a specific time? i.e.
if index.time = '***16:00:00':
df['end'] = True
I don't know how to use wildcards in this instance either.
Assuming a datetime index, you can use:
df['end'] = df.index == '16:00:00' # also works with '16:00'
example output:
col end
2022-07-20 04:52:06 0 False
2022-07-20 10:16:24 1 False
2022-07-20 10:41:42 2 False
2022-07-20 16:00:00 3 True
2022-07-20 19:07:42 4 False
reproducible input:
from pandas import Timestamp
df = pd.DataFrame({'col': {Timestamp('2022-07-20 04:52:06'): 0,
Timestamp('2022-07-20 10:16:24'): 1,
Timestamp('2022-07-20 10:41:42'): 2,
Timestamp('2022-07-20 16:00:00'): 3,
Timestamp('2022-07-20 19:07:42'): 4}})
Use dt to subset the data frame df as follows:
df[(df.time.dt.hour==16) & (df.time.dt.minute==0) & (df.time.dt.second==0)]
as outlines in the documentation.
As an example, take the frame
df = pd.DataFrame({'col_1' : [1,2,3,4], 'col_2': [65, 32, 78, 33]})
df['time'] = pd.to_datetime([1658246400, 1645621805, 1572333181, 1270483200], unit='s')
df
and observe the sub-frame:
