Help needed : Dictionary tricks in 2.2

Martin von Loewis loewis at informatik.hu-berlin.de
Mon Jan 14 10:58:06 CET 2002


pekka niiranen <krissepu at vip.fi> writes:

> Q1: Is it possible to add a method that would sort dictionary in place:
> 
>         def sortme(self):
>             keys = self.keys()
>             keys.sort()
>             AND NOW WHAT ???

No. A dictionary is not inherently sorted. If you want some sorting,
you'll need to redefine the appropriate methods, like

    def keys(self):
        k = super(defaultdict,self).keys()
        k.sort()
        return k

That, of course, will not affect the return value of .items(), or the
iterators.

> 	>>> d = {}
> 	>>> l = ['a','b','c','b']
> 	>>> dummy = map(operator.setitem, [d]*len(l), l, [])
> 	>>> d
> 	{'a': None, 'c': None, 'b': None}
> 
> Q2: How can I modify the code to create dictionary with
>     empty string -values instead of None's
> 
> 	{'a': "", 'c': "", 'b': ""}

Try

dummy = map(d.__setitem__, l, [""]*len(l))

HTH,
Martin



More information about the Python-list mailing list