对于json_dictionary中的数据： # 遍历字典键 名称错误：未定义名称'json_dictionary'

Question

def on_message(client, userdata, msg):  # The callback for when a message is received from the server.      
json_string = str(msg.payload)
json_dictionary = json.loads(json_string)  # Load JSON string to a dictionary

for data in json_dictionary:  # Loop through dictionary keys
print(data, ":", json_dictionary[data])

Answer 1

由于json_dictionary在函数内部，因此会出现错误。您需要返回或声明json_dictioanry，然后调用函数on_message。尝试这种方式：

def on_message(client, userdata, msg):  # The callback for when a message is received from the server.
json_string = str(msg.payload)
json_dictionary = json.loads(json_string)  # Load JSON string to a dictionary
return json_dictionary
json_dictionary = on_message(client,userdata,msg)
for data in json_dictionary.keys():
print(data, ":", json_dictionary[data])