How to check if dictionary has certain key (Python)

Question

I'm having a defaultdict dictionary that has keys like this:

RJECNIK['*','A']['<A>']

now i don't know how to check if there is a key, for example:

a=list(RJECNIK.keys())

gives me the list of only first keys (['*','A']). In my code I need an if statement

if key in RJECNIK: ...

But it doesn't work since I don't know how to check for a PAIR of keys in defaultdict with 2 keys.

You are confusing a multidimensional dictionary (which Python does not have) with a dictionary of dictionaries (which is what `RJECNIK` is). — chepner, Nov 05 '13 at 15:15
I don't understand your question and I don't understand that `RJECNIK['*','A']['']` notation — njzk2, Nov 05 '13 at 15:15

score 4 · Accepted Answer · answered Nov 05 '13 at 15:12

4

You need to check for both keys in both dictionaries:

key = ('*', '<A>')
if key[0] in RJECNIK and key[1] in RJECNIK[key[0]]:
    pass

answered Nov 05 '13 at 15:12

Simeon Visser

1

Seems like it could be generalised with `reduce` if the nesting is arbitrarily deep. – Marcin Nov 05 '13 at 15:41
Thank you very much, this worked! I may have confused you all, I should have made it more simple, but you got the point. – user2956251 Nov 05 '13 at 21:24

score 2 · Answer 2 · edited May 23 '17 at 12:30

2

if ("*","A") in RJECNIK:
    print "key is in dictionary"

edited May 23 '17 at 12:30

Community

answered Nov 05 '13 at 15:14

ford prefect

score 0 · Answer 3 · answered Nov 05 '13 at 15:15

0

You are using tuples as dictionary keys; '*', 'A' is just another way to spell the tuple ('*', 'A'). So

if ('*', 'A') in RJECNIK:

should be True.

answered Nov 05 '13 at 15:15

RemcoGerlich

3 Answers3