Fastest way to insert these dashes in python string?

Question

So I know Python strings are immutable, but I have a string:

c[\'date\'] = \"20110104\"

Which I would like to convert to

c[\'da         


        

Answer 1

I'd probably do so this way, not that there's a great deal of gain:

d = c['date']
c['date'] = '%s-%s-%s' % (d[:4], d[4:6], d[6:])

The big improvement (imho) is avoiding string concatenation.