Printing date from Year, Month and Day columns in Pandas-CodePudding

I am looking to add a new column - "date" to my Pandas dataframe. Below are the first 5 rows of my dataframe: First 5 rows of the dataframe As seen from the image, the first column is year, second month, and third day. Below is what I have tried to do:

df['Year'] = pd.to_datetime(df[['Year','Month','Day']])

But, I keep getting the error as below:

ValueError: cannot assemble the datetimes: time data '610101' does not match format 
'%Y%m%d' (match)

It would be great if I can get any help for the same.

CodePudding user response：

Following up on my comment, I was able to reproduce the error and solve it by adding 1900 to the year

df = pd.DataFrame({"year": [61,99], "month": [1, 2], "day": [3, 12]})
df["year"] = df["year"]   1900
df['full_date'] = pd.to_datetime(df[['year','month','day']])

Output:

    year    month   day full_date
0   1961    1   3   1961-01-03
1   1999    2   12  1999-02-12

There is a format parameter to the to_datetime method but for some reason I wasn't able to make it work. doc

df['full_date'] = pd.to_datetime(df[['year','month','day']], format="%y%m%d", infer_datetime_format=False)

this still throw the same error although I am using %y which should be 2 digit year but the error message still says it does not match this format '%Y%m%d'

CodePudding user response：

try this:

df.apply(lambda x:'%s %s %s' % (x['year'],x['month'], x['day']),axis=1)