Question

I find this design pattern comes up a lot:

try: year = int(request.GET['year'])
except: year = 0

The try block can either fail because the key doesn’t exist, or because it’s not an int, but I don’t really care. I just need a sane value in the end.

Shouldn’t there be a nicer way to do this? Or at least a way to do it on one line? Something like:

year = int(request.GET['year']) except 0

Or do you guys use this pattern too?

---

Before you answer, I already know about request.GET.get('year',0) but you can still get a value error. Wrapping this in a try/catch block to catch the value error just means the default value appears twice in my code. Even worse IMO.

Answer 1

I’d use a helper function:

def get_int(request, name, default=0):
    try:
        val = int(request.GET[name])
    except (ValueError, KeyError):
        val = default
    return val

then:

year = get_int(request, 'year')

It keeps the complexity of the try/catch in one place, and makes for tidy functions, where you have one line per parameter in your view functions.