strptime not changing date fomat in Excel

Question

I am reading a table and writing to CSV. I have some columns where I want to change the date format. Below is some code I have

    for row in out[1]:
        dt = datetime.datetime.strptime(row[18], '%Y-%m-%d %H:%M:%S.%f')
        row[18] = dt.strftime('%Y-%m-%d)
        print(row[18])

It does seem to change the date format to what I'm looking for because the print statement shows as much, but when I open the excel sheet that it wrote, the date format is like 11/12/2019 instead of 2020-11-12.

Any advice? I'm trying to prevent manually changing the format date once opening excel

Answer 1

Most likely, what Excel shows you is not what the underlying data is. Excel auto formats fields when it displays them. Hence, if it opens a CSV and sees 2020-11-12 it will recognize it is a date and display it for you as a formatted date field. If you want to save a field as TEXT that Excel will know is TEXT, then the cell has to start with a " ' ". Try adding this:

row[18] = dt.strftime('\'%Y-%m-%d')