REGEX to extract dates of all format from a text file

The code extracts dates present in any format from a text file.

A Sample test file is present at dates.txt

Date variants the code can extract :

1. 04/20/2009 04/20/09 4/20/09 4/3/09
2. Mar-20-2009 Mar 20, 2009 Mar. 20, 2009 Mar 20 2009
3. 20 Mar 2009 20 March 2009 20 Mar. 2009 20 March, 2009
4. Mar 20th, 2009 Mar 21st, 2009 Mar 22nd, 2009
5. Feb 2009 Sep 2009 Oct 2010
6. 6/2008 12/2009
7. 2009 2010

Supppose you want to match a character but do not want to capture it,use ?=character

To save in a xlsx file

from pandas import ExcelWriter 
writer = ExcelWriter(r'C:\Users\Himanshu Poddar\Desktop\Coursera courses\Applied text mining with python\assignment1dates.xlsx') 
fg.to_excel(writer,'Sheet1')
writer.save()