I need to convert markdown text to plain text format to display summary in my website. I want the code in python.
This module will help do what you describe:
http://www.freewisdom.org/projects/python-markdown/Using_as_a_Module
Once you have converted the markdown to HTML, you can use a HTML parser to strip out the plain text.
Your code might look something like this:
from BeautifulSoup import BeautifulSoup
from markdown import markdown
html = markdown(some_html_string)
text = ''.join(BeautifulSoup(html).findAll(text=True))