Convert all dates from a data frame column python-CodePudding

I have a csv file that have a column with the date that ppl get vaccinated, in format 'YYYY-MM-DD' as string. Then, my goal its add X days to the respective date, with X based on the vaccine that these person got. In order to add days to a date, i've to convert the string date to iso date, so i need to loop each element in that column conveting those dates. Im kinda new to Python and im not getting really right how do deal with it.

So i read and create a data frame with pandas, then i tryed as follow in the image: df column content and for try

I dont know why im getting this error, i tryed different ways to deal with it but cant figure it out.

Thx

CodePudding user response：

This is because the type of values is 'str,' and 'str' does not have 'fromisoformat' method. I would recommend you to convert a type of the values to 'datetime' instead of 'str,' so that you can do whatever you want regarding date calculation such as calculating X days from a specific date.

You can convert the values from 'str' to 'datetime' and do what you want as follows:

import pandas as pd
import datetime
df_reduzido['vacina_dataAplicacao'] = pd.to_datetime(df_reduzido['vacina_dataAplicacao'] , format='%Y-%m-%d')
df_reduzido['vacina_dataAplicacao'] = df_reduzido['vacina_dataAplicacao']   datetime.datetime.timedelta(days=3)
print(df_reduzido['vacina_dataAplicacao'])  # 3 days added

You can study how to deal with datetime in detail here: https://docs.python.org/3/library/datetime.html

CodePudding user response：

Thanks for your help Sangkeun. Just want to point out that, for some reason, python was returning me error saying: "'AttributeError: type object 'datetime.datetime' has no attribute 'datetime'". Then i've found a solution by calling

import datetime
from datetime import timedelta, date, datetime

Then using " timedelta() ", like this:

df_reduzido['vacina_dataAplicacao'] = ( pd.to_datetime(df_reduzido['vacina_dataAplicacao'] , format='%Y-%m-%d', utc=False)   timedelta(days=10) ).dt.date

At the end, i set ().dt.date in order to rid off the time from pd.to_datetime(). Look that i tryed to set utc=False hoping that this would do the job but nothing happened. Anyway, i'm grateful for your help.

Problem solved.