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

You are better off using string formatting than string concatenation

c['date'] = '{}-{}-{}'.format(c['date'][0:4], c['date'][4:6], c['date'][6:])

String concatenation is generally slower because as you said above strings are immutable.