Question

我试图从tvmaze api解析这个JSON。返回的JSON有一个对象None。这导致for循环中断。如何捕获此错误并跳过它？

简单代码如下所示：

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

这会导致此错误：

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

我可以看到，如果我print images结果是：

{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

我尝试了if 'medium' not in images的多个版本，但是我收到了这个错误：

TypeError: argument of type 'NoneType' is not iterable

Answer 1

首先测试一个非空对象：

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

如果not images为images，空字典，None或任何other object that tests as false，则

0为真。

你也可以明确地测试`None：

if images is None:
    continue

或者你可以反转测试：

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

或

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

如何在for循环中实现解析JSON的错误检查

1 个答案: