How do you extract epi Week from date using python?-CodePudding

I am trying to extract the epiweek from a pandas dataframe with the library "epiweeks" but i have some problems doing it.

mi code is below

import pandas as pd
from epiweeks import Week, Year

 a= [('2021-06-11 00:00:00'),
 ('2021-06-11 00:00:00'),
 ('2021-06-11 00:00:00'),
 ('2021-06-11 00:00:00'),
 ('2021-06-11 00:00:00'),
 ('2021-06-11 00:00:00'),
 ('2021-06-18 00:00:00'),
 ('2021-06-18 00:00:00'),
 ('2021-06-18 00:00:00'),
 ('2021-06-18 00:00:00'),
 ('2021-06-18 00:00:00'),
 ('2021-06-18 00:00:00'),
 ('2021-06-18 00:00:00')]
b = [25,58,65,45,47,85,96,36,25,14,25,78,75]

fecha = pd.DataFrame(list(zip(a,b)))

fecha[0] = pd.to_datetime(fecha[0])

Week.fromdate(fecha[0])

with this code I get: AttributeError: 'Series' object has no attribute 'year'

can you help me to find my wrong

Do you know another way to do it?

Thank you!

CodePudding user response：

Easy!

The only thing that you're doing wrong is you pass the whole Series to fromdate:

Week.fromdate(fecha[0])

That won't work, because Week.fromdate expects a datetime or a pandas.Timestamp. But you can call fecha[0].apply on the series, which takes a function, and calls that function for each item in the series, and adds the value that the function returns to a new series, and then returns that series. You can then add that series to the dataframe like so:

fecha['week'] = fecha[0].apply(Week.fromdate)

Or, if you want to pass some custom parameters to Week.fromdate:

fecha['week'] = fecha[0].apply(lambda x: Week.fromdate(x, ...))

Try it:

>>> fecha
            0   1    week
0  2021-06-11  25  202123
1  2021-06-11  58  202123
2  2021-06-11  65  202123
3  2021-06-11  45  202123
4  2021-06-11  47  202123
5  2021-06-11  85  202123
6  2021-06-18  96  202124
7  2021-06-18  36  202124
8  2021-06-18  25  202124
9  2021-06-18  14  202124
10 2021-06-18  25  202124
11 2021-06-18  78  202124
12 2021-06-18  75  202124

>>> fecha['week'][0]
Week(2021, 23, CDC)

>>> fecha['week'][12]
Week(2021, 24, CDC)