On May 9, 9:33 pm, python <w.g.sned...@gmail.com> wrote:
> On May 8, 12:43 pm, Benjamin Kaplan <benjamin.kap...@case.edu> wrote:
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> > On Sun, May 8, 2011 at 8:20 AM, Greg Lindstrom <gslindst...@gmail.com>
> > wrote:
> > > Is it possible to create a dictionary from a string value? Something
> > > along
> > > these lines (but that works):
>
> > >>>> mystring = "{'name':'greg','hatsize':'7 5/8'}"
> > >>>> mystring
> > > "{'name':'greg','hatsize':'7 5/8'}"
> > >>>> dict(mystring)
> > > Traceback (most recent call last):
> > > File "<string>", line 1, in <fragment>
> > > ValueError: dictionary update sequence element #0 has length 1; 2 is
> > > required
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> > > I would like to return an undetermined (at call time) number of fields
> > > from
> > > a postgres database (only 1 record) for a given request. My thought is
> > > that
> > > I could build a dictionary in the form of a string, return the string and
> > > then convert the string value to a dictionary. I can do that now, but I
> > > have to parse the string and then build the dictionary. Any thoughts or
> > > help you could provide would be appreciated.
>
> > > --greg
>
> > building the dictionary as a string seems like a hacky thing to do and
> > you might want to reevaluate your methods. But if everything in the
> > dict is a literal, you can do ast.literal_eval.
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> > > --
> > >http://mail.python.org/mailman/listinfo/python-list
>
> There are lots of possibilites and the "best" solution will very based
> on your strings' structure. List of tuples convert to dict nicely for
> example. So if your string can be parse to a list of tuples.
>
> a = [ (chr(num),num) for num in range(48,58)]
> [('0', 48), ('1', 49), ('2', 50), ('3', 51), ('4', 52), ('5', 53),
> ('6', 54), ('7', 55), ('8', 56)]
> dict(a)
> {'1': 49, '0': 48, '3': 51, '2': 50, '5': 53, '4': 52, '7': 55, '6':
> 54, '9': 57, '8': 56}
> if your string looks something like your example above. The shlex
> module might be helpful.
After re-reading your post saw you were reading from a database. Have
you looked at SQLAlchemy? It might have the functionality you are
trying to create.
--
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