What is the best way to handle exceptions?

Question

Python

Hey!
There is JSON at the input, which has its own structure, but the keys may not have values, for example:
With data, one of the keys looks like this:

"weight":[{"type":1,"value":31.0,"measurement":"g"}]

But sometimes it comes without data: there
"weight":[]
are more than a hundred keys being processed. writing on each try...except is somehow not very good.
Also, the key may not be available at all, then I will get a KeyError error
. Write a separate function with a check and call it for each key?
I would also like to handle it somehow if I haven’t registered any key in any variable, since a new key may appear and then I will know about it and write my own mapping to it.

Answer 1

Let weight be a key in some data, then:

if 'weight' in data:
    for w in data['weight']:
        t = w['type']
        # и т.д.

If weight is empty, then the loop will not be executed.
So no checks / exceptions are needed here - you have the key itself - check, since this is a list that is either empty or not.

Answer 2

See also https://github.com/Deepwalker/trafaret