Question

Suppose I have this:

list = [ { 'p1':'v1' } ,{ 'p2':'v2' } ,{ 'p3':'v3' } ]

I need to find p2 and get its value.

Answer 1

If this is what your actual code looks like (each key is unique), you should just use one dictionary:

things = { 'p1':'v1', 'p2':'v2', 'p3':'v3' }
do_something(things['p2'])

You can convert a list of dictionaries to one dictionary by merging them with update (but this will overwrite duplicate keys):

dict = {}
for item in list:
    dict.update(item)
do_something(dict['p2'])

If that’s not possible, you’ll need to just loop through them:

for item in list:
    if 'p2' in item:
        do_something(item['p2'])

If you expect multiple results, you can also build up a list:

p2s = []
for item in list:
    if 'p2' in item:
        p2s.append(item['p2'])

Also, I wouldn’t recommend actually naming any variables dict or list, since that will cause problems with the built-in dict() and list() functions.