Python：将值添加到字典内的列表中

Question

试图从名为dow的变量向weekdays:[0]添加值。在

create_data = {"startDateTime":"2015-02-23T09:05:00-0600","endDateTime":"2015-02-23T10:05:00-0600","accessories":[],"customAttributes":[{"attributeId":"3","attributeValue":""},{"attributeId":"5","attributeValue":"Yes"}],"description":"Placeholder     Description","invitees":[],"participants":[],"recurrenceRule":[{"type":"weekly","interval":2,"weekdays":[0],"repeatTerminationDate":"2015-05-24T09:50:00-0600"}],"resourceId":"15","resources":["15"],"title":"","userId":"26","startReminder":"","endReminder":""}

我搞不清是在词典中添加还是在列表中添加。在

尝试了以下方法，但却产生了以下错误：

^{pr2}$

以下是错误。在

Traceback (most recent call last):
  File "api.py", line 51, in <module>
    create_data['recurrenceRule']['weekdays'] = dow
TypeError: list indices must be integers, not str  

如何访问该值？在

Answer 1

create_data是一个字典，recurrenceRule是它的键之一。然后，它的值是一个列表：

>>> create_data['recurrenceRule']
[{'repeatTerminationDate': '2015-05-24T09:50:00-0600', 'interval': 2, 'type': 'weekly', 'weekdays': 2}]

因此，要更改weekdays，首先必须访问列表中的第一个元素：

^{pr2}$

这就是为什么会出现这样的错误：

create_data['recurrenceRule']['weekdays']
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: list indices must be integers, not str

因为您正试图使用字符串访问列表的索引（0、1、2…）。在

Answer 2

create_data['recurrenceRule']的值是list，list包含dictionary As item。因此我们必须从列表中获取项，即字典，并在其中添加weekdays键。在

create_data['recurrenceRule'][0]['weekdays'] = dow