Assignment in python for loop possible?

Question

I have a dictionary d (and a seperate sorted list of keys, keys). I wanted the loop to only process entries where the value is False - so i tried the following:

for key in keys and not d[key]:
 #do foo

I suppose my understanding of python sytax is not what i thought it was - because the assignment doesnt suppose to have happened above, and a i get an instanciation error.

The below works of course, but I'd really like to be able to use something like the code above.. possible?

for key in keys:
 if d[key]: continue
  #foo time!

Thanks!

Answer 1

Use a genex for this.

for key in (k for k in keys if not d[k]):
   ....

Answer 2

If you dict was opposite (True iff the value should be scanned) you could use:

for key in filter(d.get, keys):
    ...

Answer 3

import itertools as it

for key in it.ifilterfalse(d.get, keys):
   ...

itertools often offers the best ways to pack functionality into iterations (==loops;-).