在JSON和Python中获取特定值

Question

I'm getting a JSON data from RESTCONF HTTPS request, using the following code.

https_request = 'https://' + host + '/restconf/data/Cisco-IOS-XE-native:native/interface/'
headers = {'Content-type': 'application/yang-data+json', 'Accept': 'application/yang-data+json'}
r = requests.get(https_request, auth=(user, password), headers=headers, verify=False)
print r.json()

The JSON file I got:

{
"Cisco-IOS-XE-native:interface": {
    "GigabitEthernet": [
        {
            "name": "1",
            "description": "DON'T TOUCH ME",
            "isis": {
                "Cisco-IOS-XE-isis:metric": {
                    "value": 2
             }
            ....
        },
        {
            "name": "2",
            "isis": {
                "Cisco-IOS-XE-isis:metric": {
                    "value": 4
                } ....

        },
        {
            "name": "3",
            "shutdown": [
                null
            ],
            "isis": {
                "Cisco-IOS-XE-isis:metric": {
                    "value": 7
                }....                
        }
    ],
    "Loopback": [
        {
            "name": 0,
            "isis": {
                "Cisco-IOS-XE-isis:metric": {
                    "value": 1
                }               
    ],
    "Tunnel": [
        {
            "name": 0,
            "isis": {
                "Cisco-IOS-XE-isis:metric": {
                    "value": 3
                }....
            }
    ]
}

Basically, I want my function to return the field's "value" of isis of each interface. I tried the following code for GigabitEthernet :

value = r.json()['Cisco-IOS-XE-native:interface']['GigabitEthernet'][0]['isis']['metric']['value']

I got this error:

print Router_1.get_isis_metric()['Cisco-IOS-XE-native:interface']['GigabitEthernet'][0]['isis']['metric']['isis']
KeyError: 'metric'

Answer 1

I think, you have misspelled metric for Cisco-IOS-XE-isis:metric

Try :

value = r.json()['Cisco-IOS-XE-native:interface']['GigabitEthernet'][0]['isis']['Cisco-IOS-XE-isis:metric']['value']

Edit 1

for index in range(len(r.json()['Cisco-IOS-XE-native:interface']['GigabitEthernet'])):
    value = r.json()['Cisco-IOS-XE-native:interface']['GigabitEthernet'][index]['isis']['Cisco-IOS-XE-isis:metric']['value']
    print(value)

Answer 2

Using a list comprehension, where you iterate over the list of dictionaries and collect the value for each interface, example for GigabitEthernet

dct = {
"Cisco-IOS-XE-native:interface": {
    "GigabitEthernet": [
        {
            "name": "1",
            "description": "DON'T TOUCH ME",
            "isis": {
                "Cisco-IOS-XE-isis:metric": {
                    "value": 2
             }}

        },
        {
            "name": "2",
            "isis": {
                "Cisco-IOS-XE-isis:metric": {
                    "value": 4
                }}

        },
        {
            "name": "3",
            "shutdown": [
                None
            ],
            "isis": {
                "Cisco-IOS-XE-isis:metric": {
                    "value": 7
                }}
        }
    ]}}

result = [item['isis']["Cisco-IOS-XE-isis:metric"]['value'] for item in dct['Cisco-IOS-XE-native:interface']['GigabitEthernet']]

The output will be

[2, 4, 7]

Or to collect values for all interfaces, you can loop over the interfaces and collect the value for each interface

interfaces = ['GigabitEthernet', 'Loopback', 'Tunnel']
result = [item['isis']["Cisco-IOS-XE-isis:metric"]['value'] for interface in interfaces for item in dct['Cisco-IOS-XE-native:interface'][interface]]
print(result)

The output will be

[2, 4, 7, 1, 3]