Python search by value

Question

I need a proper solution to search for a key in a nested data structures in Python. Lets assume that I have variable with value \'check\' and dict like this:

Answer 1

Standard approach:

for k, v in SERVICES.items(): # or iteritems in Python 2
    if 'check' in v:
        print(k) # 'domain'
        break

If you expect to have multiple keys matching the condition, just remove break.

Functional approach:

>>> next(filter(lambda x: 'check' in SERVICES[x], SERVICES))
'domain'