Examkin

Soru

Zorluk: ZorInterpreting JSON Encoded Data

A Python network automation script stores the following JSON response from a Cisco Catalyst Center API in a dictionary variable named `data`:

{
"response": [
{
"siteId": "USA-NY-OFFICE",
"devices": [
{
"hostname": "Core-Rtr-01",
"managementIp": "192.168.1.1",
"upTimeSeconds": 86400,
"isReachabilityHealthy": true,
"modules": [
{"slot": 0, "status": "OK", "serialNumber": "FOC12345678"},
{"slot": 1, "status": "FAIL", "serialNumber": "FOC87654321"}
]
},
{
"hostname": "Dist-Sw-01",
"managementIp": "192.168.1.2",
"upTimeSeconds": 43200,
"isReachabilityHealthy": false,
"modules": [
{"slot": 0, "status": "OK", "serialNumber": "FOC11223344"}
]
}
]
}
]
}

Which Python expression correctly retrieves the serial number of the failed module on `Core-Rtr-01`, and what is the data type of the returned value?

  1. data["response"][0]["devices"][0]["modules"][1]["serialNumber"] returning a stringCevap
  2. B
    data["response"][1]["devices"][1]["modules"][2]["serialNumber"] returning a string
  3. C
    data["response"][0]["devices"][0]["modules"][1]["serialNumber"] returning an integer
  4. D
    data["response"]["devices"][0]["modules"][1]["serialNumber"] returning a string

Cevap

The expression `data["response"][0]["devices"][0]["modules"][1]["serialNumber"]` correctly retrieves the string value `"FOC87654321"`.
The key `"response"` maps to a list whose first element is at index `0`. Within that dictionary, `"devices"` contains a list where `Core-Rtr-01` is at index `0`. Inside that object, `"modules"` is a list containing the failed module as its second element (index `1`). Accessing `"serialNumber"` extracts `"FOC87654321"`, which is enclosed in double quotes and parsed as a string.

Adım Adım Çözüm

1
Examine the top-level structure of the JSON payload.
The top-level structure is a dictionary where key `"response"` maps to a JSON array `[...]`. The array contains a single dictionary at index `0`.
Accessing elements inside the top-level array requires `data["response"][0]`.
2
Locate the target device within the `"devices"` array.
The `"devices"` key maps to a list. `Core-Rtr-01` is the first element, situated at index `0`.
Python list indices start at `0` (`["devices"][0]`).
3
Locate the failed module within the `"modules"` list.
The `"modules"` array for `Core-Rtr-01` contains two dictionary items. Slot 0 is at index `0` and slot 1 (status `"FAIL"`) is at index `1`.
The second element in a zero-indexed list is index `1` (`["modules"][1]`).
4
Extract the key and determine the Python data type.
Accessing key `"serialNumber"` yields `"FOC87654321"`. Surrounding double quotes signify a string data type (`str`).
Quoted literal values in JSON map directly to string types in Python.

Anahtar Kavram

Interpreting nested JSON arrays versus objects and mapping JSON values to Python data types.
Bu soruyu puanla

Konular

Interpreting JSON Encoded Data

Bu konudan daha fazla soru