Trying to get a value from a JSON in python-CodePudding

I am trying to access a value in a json file using python. In the imgur link, the value I am trying to access is the "NUM" nested in "args". My main logic is reading in the JSON file, then using pandas to normalize the json.I have tried using .loc to try and find 'args' but I need help with another way or option. [1]: https://i.stack.imgur.com/n6hOg.png

Here is my code snippet along with the terminal error I am getting

def readInJSON(json):
    df = pandas.json_normalize(json)
    goto_rows = [i for i in df.loc[df['mnemonic'] == 'PLD_CCD_EXPOSE_CLOSED'].index]
    commandDates = list(df['utc_time'])
    numIDs =  list(df['args'])  #tried using list typing 
    print(type(df['args']))  #couldnt get a typing from it either 
    args = df['args']        #tried just using it like a regular list 
    args = [i for i in df.loc[df['args']]]  #tried using .loc from pandas as well

File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/pandas/core/frame.py", line 3505, in getitem indexer = self.columns.get_loc(key) File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/pandas/core/indexes/base.py", line 3623, in get_loc raise KeyError(key) from err KeyError: 'args'

CodePudding user response：

This is how you can access value of NUM:

import json

file = open('data.json')

data = json.load(file)

NUM = data[1]["args"]["NUM"]

# NUM = 20.0

file.close()

CodePudding user response：

The JSON structure appears to be a list of dictionaries. Those dictionaries may or may not have a 'args' key. The value associated with 'args' is expected to be a dictionary. That dictionary may contains a 'NUM' key. If 'NUM' exists, append its value to a list. Return the list.

def readInJSON(json):
    numvals = []
    for d in json:
        if (args := d.get('args')):
            if isinstance(args, dict) and (num := args.get('NUM')):
                numvals.append(num)
    return numvals

A better approach might be to write the function so that it handles the input JSON file like this:

import json

def readInJSON(filename):
    with open(filename) as jdata:
        numvals = []
        for d in json.load(jdata):
            if (args := d.get('args')):
                if isinstance(args, dict) and (num := args.get('NUM')):
                    numvals.append(num)
        return numvals