Python (DICT) - 用 JSON 填充 - 无法在请求中使用变量

Question

我想知道你是否可以帮我解决我目前正在处理的一段代码。我是 Python 新手，这是我尝试编写的第一个主要脚本之一。

import json, sys
from pprint import pprint
#Importing workbench json output into the python script.
with open('jsonoutput.json') as data_file:
    data = json.load(data_file)

#Sets the verible for the while loop.
x = int(0)

while x <= 1:
    y = x
    print type(data)
    jdata = data["result"]["items"][y]["tagValues"]["IdDevicesMap"]["value"]
    if setup_1(jdata) == True:
        Default_1 += 1
    else:
        print "exiting"

运行时出现错误:

Traceback (most recent call last):
  File "main.py", line 47, in <module>
    jdata = data["result"]["items"][y]["tagValues"]["IdDevicesMap"]["value"]
KeyError: 'tagValues'

顺便说一句，当我手动将列表编号 [y] 设置为 1 时，代码运行完美。所以这就像我将变量 [y] 输入到请求中的方式有​​问题。

Answer 1

我很确定您读到的 json 中并不都有 tagValues。您可能想尝试 try: 和 except:

import json, sys
from pprint import pprint
#Importing workbench json output into the python script.
with open('jsonoutput.json') as data_file:
    data = json.load(data_file)
x = 0
while True:
    try:
        jdata = data["result"]["items"][x]["tagValues"]["IdDevicesMap"]["value"]
        if setup_1(jdata) == True:
            Default_1 += 1
        else:
            print "exiting"
            break
    except KeyError:
        print data["result"]["items"][x]
        pass
    x+=1

以Pythonic方式做到这一点:

import json, sys
from pprint import pprint
#Importing workbench json output into the python script.
with open('jsonoutput.json') as data_file:
    data = json.load(data_file)

for x, d in enumerate(data["result"]["items"]): #in case you need a counter
    try:
        jdata = d["tagValues"]["IdDevicesMap"]["value"]
        if setup_1(jdata) == True:
            Default_1 += 1
        else:
            print "exiting"
            break
    except KeyError:
        pass