python %s

replaced by given string.

given_string = "I think %s is a perfectly normal thing to do in public."
def sub1(s):
     return given_string % s

given_string2 = "I think %s and %s are perfectly normal things to do in public."
def sub2(s1, s2):
    return given_string2 % (s1, s2)

string substitution

given_string2 = "I'm %(nickname)s. My real name is %(name)s, but my friends call me %(nickname)s."
def sub_m(name, nickname):
    return given_string2 % {"nickname": nickname, "name" : name}
    
print sub_m("Mike", "Goose")

replacement

def escape_html(s):
   for (i, o) in (("&", "&"),
                (">", ">"),
                ("<", "&lt;"),
                ('"', "&quote;")):
        s = s.replace(i, o)
    return s

 print escape_html('>')

import cgi
def escape_html(s):
   return cgi.escape(s, quote = True)

 print escape_html('"hello, & = &amp;"')