Python Dataframe column of dates - change format to yyyy-mm-dd

Question

df['date'] is the column I am working with.

The data is in the 'date' column is in the day/month/year format, like this: 7/12/2019. How would I modify this column to give me Year-month-day, or 2019-07-12?

This is what I have tried, but still is not working: df['date'] = pd.to_datetime(str(df['date']))

Answer 1

Try:

df.loc[:,'date'] = pd.to_datetime(df.loc[:,'date'], format="%d/%m/%yyyy")

Let me know if it works!

EDIT #1

Since, the "date" column has mixed formats, try:

def date_format(df):
    for index, row in df.iterrows():
        try:
            df.loc[index, row['date']] = pd.to_datetime(df.loc[index, row['date']], format="%d/%m/%yyyy")
        except ValueError as e:
            df.loc[index, row['date']] = pd.to_datetime(df.loc[index, row['date']], format="%m/%d/%yyyy")
    return df

Answer 2

You can use dt.strftime if you need to convert datetime to other formats (but note that then dtype of column will be object ( string )):

import pandas as pd

df = pd.DataFrame({'DOB': {0: '26/1/2016', 1: '26/1/2016'}})
print (df)
         DOB
0  26/1/2016 
1  26/1/2016

df['DOB'] = pd.to_datetime(df.DOB)
print (df)
         DOB
0 2016-01-26
1 2016-01-26

df['DOB1'] = df['DOB'].dt.strftime('%m/%d/%Y')
print (df)
         DOB        DOB1
0 2016-01-26  01/26/2016
1 2016-01-26  01/26/2016