"%(a)s ... %(b)s" % {'a': foo, 'b': '%(b)s'}

[Darrell]

import re

MAIL = '''From: someone <%(email)s>
Subject: test

this is feedback.py %(version)s
'''

dic={'version': "1.1"}

def format(fmt, dic):
    converted=[]
    nonConverted=[]

    def func(mo, dic=dic, conv=converted, nonConv=nonConverted):
        k,t=mo.groups()
        if dic.has_key(k):
            conv.append(k)
            return mo.group(0)%dic
        nonConv.append(k)
        return mo.group(0)

    return re.compile('%\((.*?)\)(\w)').sub(func,fmt), converted,
nonConverted

result=format(MAIL, dic)
print result[0]
print 'Converted:', result[1]
print 'Not converted:', result[2]

######### output
From: someone <%(email)s>
Subject: test

this is feedback.py 1.1

Converted: ['version']
Not converted: ['email']


--Darrell
----- Original Message -----
From: "Gerrit Holl" <gerrit.holl at pobox.com>
>
> This is ugly! Isn't there a better way to fill in just SOME of the %(...)s
> values in a string and leave the rest as is?
>