excel - Convert the column type from object to date format - python

Question

I have concatenated two dataframes, the column type before concatenation was datetime, but after concatenation the column type changed to object, and when I export to excel it completely changed!

here is the two dataframe:

df_last_month:

project number	status	Project Naming	CF	VPC	CO	MA
A	Planned	DH	2021-01-26	2021-03-16	2021-11-16	2023-10-10
B	frozen	DH	2017-12-01	2018-12-18	2019-07-26	2022-02-18
C	Planned	DH	2017-12-01	2018-12-18	2019-07-26	2022-02-18
D	Planned	HH	2017-12-01	2018-12-18	2019-07-26	2022-02-18

question from:https://stackoverflow.com/questions/65887358/convert-the-column-type-from-object-to-date-format-python

Answer 1

How about converting the Datetime columns to string before concatenating the two dataframes. This way you can have the output you wanted.

from pandas.api.types import is_datetime64_any_dtype
    
for col in df_current_month.columns:
        if is_datetime64_any_dtype(df_current_month[col]):
            df_current_month[col] = df_current_month[col].dt.strftime('%Y-%m-%d')

df_current_month['CF'].head()
0    2021-10-01
1    2017-01-12
2    2017-01-12
3    2017-01-12
4    2017-01-12
Name: CF, dtype: object

Unfortunately, you have to do this for both dataframes.