Merging two lists of data (Pythonic way)

[Paul Rubin]

"SMB" <sean at buildingonline.com> writes:
> What I am doing is looking for a pythonic way to parse the LIST2 "code" 
> values and make appropriate changes to to each dictionary if the "code" 
> value is the first element of a list in LIST1.
> 
> The final result may look like this given that the change is adding a new 
> key/value of "VERIFIED"/1 for the matches.

Untested:

from sets import Set
vvals = Set(a[0] for a in LIST1)    # get all the List1 first elt. values
for d in LIST2:
   if d['code'] in vvals:
      d['VERIFIED'] = 1

> I know I could do this with two for loops, but am looking for a better 
> solution maybe involving list comprehension.

I think if list1 is potentially long, the main thing is to avoid n**2
running time, which means use a set or dict to do the lookups, like
above.