Do dictionaries have a has key method? I'm checking for 'None' and I'm having issues

Question

I have 2 dictionaries, and I want to check if a key is in either of the dictionaries.

I am trying:

if dic1[p.sku] is not None:

I wish there was a hasKey method, anyhow.

I am getting an error if the key isn't found, why is that?

Answer 1

Use the in operator:

if p.sku in dic1:
    ...

(Incidentally, you can also use the has_key method, but the use of in is preferred.)

Answer 2

They do:

if dic1.has_key(p.sku):

Answer 3

if dic1.get(p.sku) is None: is the exact equivalent of what you're trying except for no KeyError -- since get returns None if the key is absent or a None has explicitly been stored as the corresponding value, which can be useful as a way to "logically delete" a key without actually altering the set of keys (you can't alter the set of keys if you're looping on the dict, nor is it thread-safe to do so without a lock or the like, etc etc, while assigning a value of None to an already-existing key is allowed in loops and threadsafe).

Unless you have this kind of requirement, if p.sku not in dic1:, as @Michael suggests, is vastly preferable on all planes (faster, more concise, more readable, and so on;-).