Python - Find biggest of string dates

List of datetime objects

We can use max function to find biggest of a list of datetime objects.

from datetime import datetime

datelist = [datetime(2020, 10, 15, 0, 0), datetime(2021, 12, 22, 0, 0), datetime(2022, 1, 18, 0, 0), datetime(2021, 10, 15, 8, 40, 50), datetime(2018, 8, 14, 22, 35)]
print("Biggest Date: " + str(max(datelist)))

Output: Biggest Date: 2022-01-18 00:00:00

List of string dates in same format

For a list of string dates which are in same format, we just need to use strptime() to convert string to datetime objects and then apply max function.
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from datetime import datetime datelist = ['2020/10/15', '2019/10/15', '2021/10/15'] dtlist = [datetime.strptime(dt, '%Y/%m/%d') for dt in datelist] print("Biggest Date: " + str(max(datelist)))
Output: Biggest Date: 2021/10/15

List of string dates in different format

If the list contains string dates in multiple formats, we will have to loop through each item and use a try...except block to find the correct format.
A function formatDates() is created here to handle the logic.

from datetime import datetime

def formatDates(datestosort):
    formatlist = ['%Y/%m/%d', '%m-%d-%y', '%y.%m.%d', '%m-%d-%Y %H:%M:%S', '%Y.%m.%d %H:%M']

    newdtlist = []
    for dt in datestosort:
        for fl in formatlist:
            try:
                newdtlist.append(datetime.strptime(dt, fl))
                break
            except:
                pass
        
    return newdtlist

datelist = ['2020/10/15', '12-22-21', '22.01.18', '10-15-2021 08:40:50', '2018.08.14 22:35']
dtlist = formatDates(datelist)
print("Biggest Date: " + str(max(dtlist)))

Output: Biggest Date: 2022-01-18 00:00:00

Python - Find biggest of string dates

List of datetime objects

List of string dates in same format

List of string dates in different format