string formatting with missing dictionary key

[Jeff Epler]

(Requires Python 2.2)

class D(dict):
    def __getitem__(self, item):
        if not self.has_key(item): return "default"
        return super(D, self).__getitem__(item)
        
print "%(a)s ; %(d)s; %(e)s" % D({'a':1, 'b':2, 'c':3})