Question

Is there a single line method to check whether a Python 2d dict has an inner key/value?

Right now i do somethng like this:

if d.has_key(k1):
    if d[k1].has_key(k2): 
        # do something

Is there a better way to do this?

Thanks

Answer 1

if k2 in d.get(k1, {}):
    # do something

The above fragment is nice if you don’t care about whether k1 actually exists or not and merely want to know whether k2 exists inside of it if it does exist. As you can see from my code snippet, I prefer the in operator, but you could just as easily say

if d.get(k1, {}).has_key(k2):
    # do something

if you prefer that idiom, but the has_key method has been deprecated in Python 3.x, so you should probably avoid it.