Printing variable names

[Scott David Daniels]

Mark McEahern wrote:
> Mike wrote:
>> mylist = [a, b, c]
>>
>> I want to print out the names of the variables in mylist (not the
>> values of a, b, and c).  How do I go about doing this.  Thanks.
>> Mike
> ... One idea is to use a dictionary instead.  Then:
> for key, value in mydict.iteritems():
>    print '%(key)s = %(value)s' % locals()
> I'm curious what problem you're trying to solve.

Mark's questions are very much on target.  If the purpose is debugging,
you might be satisfied with something like:

     def vnames(value, *dicts):
         """From a value and some dictionaries and give names for the 
value"""
         result = []
         for d in dicts:
             result.extend([key for key, val in d.iteritems()
                            if val is value])
         result.append(repr(value))
	return result

Which you might use like:

     a,b,c = 1,2,3
     d,e,f = 5,4,3

     for v in range(10):
         print v, vnames(v, locals(), globals())

Note: You probably need only locals or globals if you are at the top
       level of an interpreter such as Idle or the python shell.
        You might prefer '==' to 'is', but remember that 0.0 == 0 == 0L.

-Scott David Daniels
Scott.Daniels at Acm.Org