Advanced string formatting in Python

You can use the dictionary type of formatting:

s='arbit'
string='%(key)s hello world %(key)s hello world %(key)s' % {'key': s,}

You can use advanced string formatting, available in Python 2.6 and Python 3.x:
incoming = 'arbit'
result = '{0} hello world {0} hello world {0}'.format(incoming)