Edit configuration file through python

import re 
pat = re.compile('ENABLEPRINTER|PRINTERLIST|PRNT1.PORT')

def jojo(mat,dic = {'ENABLEPRINTER':'y',
                    'PRINTERLIST':'PRNT3',
                    'PRNT1.PORT':'734'} ):
    return dic[mat.group()]

with open('configfile','rb+') as f:
    content = f.read()
    f.seek(0,0)
    f.write(pat.sub(jojo,content))
    f.truncate()

Before:

ENABLEPRINTER=n 
PRINTERLIST=PRNT1, PRNT2  

PRNT1.PORT=9600 
PRNT1.BITS=8

After:

y=n 
PRNT3==PRNT1, PRNT2  

734=9600
PRNT1.BITS=8

Too simple to be definitive. Say what are the errors or weaknesses.

The advantage of regexes is they can be modulated easily to particular cases.

.

EDIT:

I've just seen that:

"what i want to do is assign a new value to the variable "

you could inform of that earlier !

Could you give an exemple of file before / after , please.

.

EDIT 2

Here's the code to change the values of certain variables in a file:

import re
from os import fsync

def updating(filename,dico):

    RE = '(('+'|'.join(dico.keys())+')\s*=)[^\r\n]*?(\r?\n|\r)'
    pat = re.compile(RE)

    def jojo(mat,dic = dico ):
        return dic[mat.group(2)].join(mat.group(1,3))

    with open(filename,'rb') as f:
        content = f.read() 

    with open(filename,'wb') as f:
        f.write(pat.sub(jojo,content))



#-----------------------------------------------------------

vars = ['ENABLEPRINTER','PRINTERLIST','PRNT1.PORT']
new_values = ['y','PRNT3','8310']
what_to_change = dict(zip(vars,new_values))


updating('configfile_1.txt',what_to_change)

Before:

ENABLEPRINTER=n 
PRINTERLIST=PRNT1, PRNT2  

PRNT1.PORT=9600 
PRNT1.BITS=8

After:

ENABLEPRINTER=y 
PRINTERLIST=PRNT3

PRNT1.PORT=8310 
PRNT1.BITS=8