如何在Python中使用索引获取字典中的键名和值

Question

I have below json:

{
    "Static Data": {
        "Maximum Target": "UI-A@supervision-report-production-data-data-1-4:statistics-1:maximum_target",
        "Sigma": "UI-A@supervision-report-production-data-data-1-4:statistics-1:sigma2",
        "Variation Coefficient": "UI-A@supervision-report-production-data-data-1-4:statistics-1:cv",
        "Web Width": "UI-A@supervision-report-production-data-data-1-4:statistics-1:fullwidth"
    },

    "Section": "Winder-A1-roll-1-4:section",
    "StartDateTime": "Winder-A1-3:startTimestamp",
    "StopDateTime": "Winder-A1-3:stopTimestamp"

}

below is the code:

json_data = open(configs_path)
data = json.load(json_data)
json_data.close()

index = 2

print(data['Static Data'][index])

Based on index , I want to get the key name and value of the dict. How can I do this.?

Answer 1

You can convert a dictionary into a list of key / value pairs

kvpairs = list(data.items())

then kvpairs[0][0] will be the first key and kvpairs[0][1] the first value.

This is not normally needed very often because the accessing a dictionary by index is somewhat a strange requirement.

Note that the conversion to list is necessary if you want to access entries by index, as otherwise the object returned from items is only usable for iteration.

If you need instead what is much more common and is iterating over an array then a simple loop using for ... in will do:

for key, value in data.items():
    ...

Answer 2

If you are using an updated version of Python (3.6≤), skip to the second step, otherwise, you will have to follow the first step of loading your JSON in order:

Step 1 - Load in Order (On older Python versions (<3.6)):

To do that, you will have to load your json with an OrderedDict as the key hook:

from collections import OrderedDict

with open(configs_path) as fd:
    json_data = json.load(fd, object_pairs_hook=OrderedDict)

Step 2 - Convert the dictionary (Or inner ones) to list:

You will then have to convert your dictionary into list, so you can access it by index, assuming you want to access only the inner dicts with an index, then you should do something like:

for key, value in json_data.items():
    if isinstance(value, dict):
        json_data[key] = list(value.items())

Then you can access it like:

index = 2
print(json_data['Static Data'][index])