Thingspeak：用Python解析json响应

Question

我想创建一个使用Python的Alexa技能来使用传感器上传到Thingspeak的数据。在我只使用一个特定值的情况下是非常容易的，Thingspeak的响应只是值。当我想使用几个值来总结大气压力来确定趋势时，响应是一个json对象，如下所示：

{"channel":{"id":293367,"name":"Weather Station","description":"My first attempt to build a weather station based on an ESP8266 and some common sensors.","latitude":"51.473509","longitude":"7.355569","field1":"humidity","field2":"pressure","field3":"lux","field4":"rssi","field5":"temp","field6":"uv","field7":"voltage","field8":"radiation","created_at":"2017-06-25T07:35:37Z","updated_at":"2018-08-04T12:11:22Z","elevation":"121","last_entry_id":1812},"feeds":
[{"created_at":"2018-10-21T18:11:45Z","entry_id":1713,"field2":"1025.62"}, 
 {"created_at":"2018-10-21T18:12:05Z","entry_id":1714,"field2":"1025.58"}, 
 {"created_at":"2018-10-21T18:12:25Z","entry_id":1715,"field2":"1025.56"}, 
 {"created_at":"2018-10-21T18:12:45Z","entry_id":1716,"field2":"1025.65"}, 
 {"created_at":"2018-10-21T18:13:05Z","entry_id":1717,"field2":"1025.58"}, 
 {"created_at":"2018-10-21T18:13:25Z","entry_id":1718,"field2":"1025.63"}]

我现在从

^{pr2}$

json对象有点递归，它是一个列表，其中包含一个以数组为值的元素。 现在我不太确定如何迭代数组中键“field2”的值。我对Python和json非常陌生。也许谁能帮我？在

提前谢谢！在

Answer 1

我刚想好了，一切如期而至。 您必须从dict中获取entries数组，然后遍历项目列表并将值打印到键field2。在

# Get entries from the response
entries = json_object["feeds"]

# Iterate through each measurement and print value
for entry in entries:
  print entry['field2']

Answer 2

这与json无关—一旦json.load()解析了json字符串，您得到的是一个普通的python对象（通常是dict，有时是列表，但这是合法的字符串、int、float、boolean或None）。在

it is a list containing a list with an element with an array as the value.

实际上它是一个dict，有两个键"channel"和{}。第一个有另一个dict for value，第二个是dicts的list。如何使用dict和list在FWIW中有大量的文档

• https://docs.python.org/3/tutorial/datastructures.html#dictionaries
• https://docs.python.org/3/library/stdtypes.html#mapping-types-dict
• https://docs.python.org/3/tutorial/introduction.html#lists
• https://docs.python.org/3/library/stdtypes.html#sequence-types-list-tuple-range

这里，您要查找的值存储在“feeds”键中dicts的“field2”键下，因此您需要的是：

# get the list stored under the "feeds" key
feeds = json_object["feeds"]

# iterate over the list:
for feed in feeds:
    # get the value for the "field2" key
    print feed["field2"]

Answer 3

你有一本字典。使用键访问值

例如：

json_object = {"channel":{"id":293367,"name":"Weather Station","description":"My first attempt to build a weather station based on an ESP8266 and some common sensors.","latitude":"51.473509","longitude":"7.355569","field1":"humidity","field2":"pressure","field3":"lux","field4":"rssi","field5":"temp","field6":"uv","field7":"voltage","field8":"radiation","created_at":"2017-06-25T07:35:37Z","updated_at":"2018-08-04T12:11:22Z","elevation":"121","last_entry_id":1812},"feeds":
[{"created_at":"2018-10-21T18:11:45Z","entry_id":1713,"field2":"1025.62"}, 
 {"created_at":"2018-10-21T18:12:05Z","entry_id":1714,"field2":"1025.58"}, 
 {"created_at":"2018-10-21T18:12:25Z","entry_id":1715,"field2":"1025.56"}, 
 {"created_at":"2018-10-21T18:12:45Z","entry_id":1716,"field2":"1025.65"}, 
 {"created_at":"2018-10-21T18:13:05Z","entry_id":1717,"field2":"1025.58"}, 
 {"created_at":"2018-10-21T18:13:25Z","entry_id":1718,"field2":"1025.63"}]}

for entry in json_object["feeds"]:
    print entry["field2"]

输出：

^{pr2}$