How to simply catch an empty list in Python from JSON API?

Question

I need to return a bunch of SKUs from a JSON API response but sometimes it's "empty":

{'products': [], 'request_speed': 0.0015690326690674}

This code works when there are products but raises an IndexError when there are no products:

data = json.loads(r.text)
print(data)
if not data['products'][0]:
    print("something")
    for key in data['products']:
        print(key['info']['sku'])
else:
    print("nothing")

And this always has "something" because there is always a "products" [] in the response:

data = json.loads(r.text)
print(data)
if not data['products']:
    print("something")
    for key in data['products']:
        print(key['info']['sku'])
else:
    print("nothing")

I know I could add a try/except to the first example but it seems a round the houses way of achieving something.

Is there a more shorthand way of achieving this? I did think:

if 'info' in data['products']:

Was the pythonic way but this always returns "nothing".

Your check is wrong. if not data['products']: should be if data['products']:. You could also check: if any(data['products']): — Jan Zeiseweis
– Jan Zeiseweis, Commented Oct 16, 2017 at 10:44
Yes, the second attempt should work if you fix the condition. — mkrieger1
– mkrieger1, Commented Oct 16, 2017 at 10:49

Jan Zeiseweis · Accepted Answer · 2017-10-16 10:54:35Z

1

You don't have to do this check at all.

You can simply iterate over the empty list. It won't do anything if there is nothing.:

data = json.loads(r.text)
for key in data['products']:
    print(key['info']['sku'])

EDIT

If you want to stop your iteration:

if not data['products']:
    break
for key in data['products']:
    print(key['info']['sku'])

edited Oct 16, 2017 at 10:54

answered Oct 16, 2017 at 10:49

Jan Zeiseweis

3,7482 gold badges19 silver badges24 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Johnny John Boy Over a year ago

Except this code is in a while loop to iterate through page 1, 2, etc so I need to check whether this is the last record as the API returns no products.

Johnny John Boy Over a year ago

The if not data[‘products’]: will always be true as there is always products, just it’s an empty list when there aren’t any.

Jan Zeiseweis Over a year ago

Try to execute this on your interpreter: if not []: print('this list is empty')

Johnny John Boy · Accepted Answer · 2017-10-16 10:46:08Z

0

if 'info' in r.text:

Also works. Which option is best practice and I will mark as correct?

answered Oct 16, 2017 at 10:46

Johnny John Boy

3,3266 gold badges34 silver badges60 bronze badges

Comments

DRPK · Accepted Answer · 2017-10-16 11:26:45Z

0

check its len, like this:

data = json.loads(r.text)

print(data)

if len(data['products']) > 0:
    print("something")
    for key in data['products']:
        print(key['info']['sku'])

else:
    print("nothing")

edited Oct 16, 2017 at 11:26

answered Oct 16, 2017 at 10:43

DRPK

2,0912 gold badges16 silver badges28 bronze badges

Collectives™ on Stack Overflow

How to simply catch an empty list in Python from JSON API?

3 Answers 3

3 Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

3 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related