Want to reduce steps of an operation with dictionaries

pretoriano_2001 at hotmail.com pretoriano_2001 at hotmail.com
Wed Oct 25 15:53:14 CEST 2006


James:
Your solution works for me, many, many thanks for your help and many
thanks for the time, teaching and reflections I received from all the
guys that participated in this thread.


James Stroud wrote:
> pretoriano_2001 at hotmail.com wrote:
> > Hello:
> > I have next dictionaries:
> > a={'a':0, 'b':1, 'c':2, 'd':3}
> > b={'a':0, 'c':1, 'd':2, 'e':3}
> > I want to put in a new dictionary named c all the keys that are in b
> > and re-sequence the values. The result I want is:
> > c={'a':0, 'c':1, 'd':2}
> > How can I do this with one line of instruction?
> >
> > I attempted the next but the output is not the expected:
> > c=dict([(k,v) for v,k in enumerate(a) if b.has_key(k)])
> > erroneously (for me) gets:
> > {'a': 0, 'c': 2, 'd': 3}
> >
> > Thanks for your help.
> >
> I think you have the right idea if I understand what you want:
>
> c = dict(((k,v) for (v,k) in enumerate(x for x in a if b.has_key(x))))
>
> --
> James Stroud
> UCLA-DOE Institute for Genomics and Proteomics
> Box 951570
> Los Angeles, CA 90095
> 
> http://www.jamesstroud.com/




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