How to implement error checking parsing JSON in a for loop

Question

I am trying to parse this JSON from the tvmaze api. The JSON that is returned has one object as None. This is causing the for loop to break. How can I catch this error and skip it?

The simple code looks like this:

import requests,re,json


url = "http://api.tvmaze.com/shows/1/seasons"
html = requests.get(url).json()
for season in html:
    images = season['image']
    test = images['medium']
    print test

This results in this error:

Traceback (most recent call last):
  File "C:/Python27/test_maze.py", line 7, in <module>
    if 'medium' not in images:
TypeError: argument of type 'NoneType' is not iterable

I can see that if I print imagesthe result is:

{u'medium': u'http://static.tvmaze.com/uploads/images/medium_portrait/24/60941.jpg', u'original': u'http://static.tvmaze.com/uploads/images/original_untouched/24/60941.jpg'}
{u'medium': u'http://static.tvmaze.com/uploads/images/medium_portrait/24/60942.jpg', u'original': u'http://static.tvmaze.com/uploads/images/original_untouched/24/60942.jpg'}
None

I have tried multiple versions of if 'medium' not in images, but I get this error:

TypeError: argument of type 'NoneType' is not iterable

Your if 'medium' not in images: line is not present in the code you show. — Martijn Pieters
– Martijn Pieters, Commented Mar 10, 2018 at 19:49

Martijn Pieters · Accepted Answer · 2018-03-10 19:50:17Z

1

Just test for a non-empty object first:

for season in html:
    images = season['image']
    if not images:
        continue
    test = images['medium']

not images is true if images is None, an empty dictionary, 0, or any other object that tests as false.

You could also explicitly test for `None:

if images is None:
    continue

or you could invert the tests:

if images and 'medium' in images:
    #  there is a medium image

or

if images is not None and 'medium' in images:
    #  there is a medium image

answered Mar 10, 2018 at 19:50

Martijn Pieters

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