Date format issue

Data Science, AI and ML
#1

date column in csv file has some dates with hyphen seperator eg:12-05-2012 3:05 and remaining with a / eg: 12/05/2012 3:05 due to which all the dates are not getting grouped as per month and year when I click on filter drop down in the date column. I tried formatting in date but the backslash simply doesnt go away. Need solution for this