Let's assume you want to overwrite the same file:

import json

with open('data.json', 'r') as data_file:
    data = json.load(data_file)

for element in data:
    element.pop('hours', None)

with open('data.json', 'w') as data_file:
    data = json.dump(data, data_file)

dict.pop(<key>, not_found=None) is probably what you where looking for, if I understood your requirements. Because it will remove the hours key if present and will not fail if not present.

However I am not sure I understand why it makes a difference to you whether the hours key contains some days or not, because you just want to get rid of the whole key / value pair, right?

Now, if you really want to use del instead of pop, here is how you could make your code work:

import json

with open('data.json') as data_file:
    data = json.load(data_file)

for element in data:
    if 'hours' in element:
        del element['hours']

with open('data.json', 'w') as data_file:
    data = json.dump(data, data_file)

EDIT So, as you can see, I added the code to write the data back to the file. If you want to write it to another file, just change the filename in the second open statement.

I had to change the indentation, as you might have noticed, so that the file has been closed during the data cleanup phase and can be overwritten at the end.

with is what is called a context manager, whatever it provides (here the data_file file descriptor) is available ONLY within that context. It means that as soon as the indentation of the with block ends, the file gets closed and the context ends, along with the file descriptor which becomes invalid / obsolete.

Without doing this, you wouldn't be able to open the file in write mode and get a new file descriptor to write into.

I hope it's clear enough...

SECOND EDIT

This time, it seems clear that you need to do this:

with open('dest_file.json', 'w') as dest_file:
    with open('source_file.json', 'r') as source_file:
        for line in source_file:
            element = json.loads(line.strip())
            if 'hours' in element:
                del element['hours']
            dest_file.write(json.dumps(element))

One of approaches from Remove element from list when using enumerate() in python - a loop over a copy of the list referred as [:] - works too:

for a in myData['myArray'][:]:
  if (a['name'] == u'bad'):
     myData['myArray'].remove(a)

Thanks everyone!

Assuming, the file in which you have your JSON is called file.json:

import json
with open('file.json') as f:
    d = json.load(f)
    for key, value in d.items():
        del value['id']
        d[key] = value

Alternative you can use the following:

import json
with open('file.json') as f:
    d = json.load(f)
    for key, value in d.items():
        value.pop('id', None) // this will not crash if the element has no key 'id'

As one of the commenters mentioned, you aren't indexing into the correct field in your json dictionary.

To fix:

with open('input.json',encoding='utf8') as in_file:
    data = json.load(in_file)
    for element in data:
        del element["fields"]["idb_metric"]

    print(element["fields"])

It may also save you some headaches if you make sure that the key exists before trying to delete it. This is one way to check if it exists:

with open('input.json',encoding='utf8') as in_file:
    data = json.load(in_file)
    for element in data:
        if element.get("fields") is not None:
            if element["fields"].get("idb_metric") is not None:
                del element["fields"]["idb_metric"]
    print(element["fields"])

As an answer to your edited question, don't use elif:

if 'idb_metric' in element["fields"]:
    print("Found idb_metric!")
    del element['fields']['idb_metric']
    print(element)

if 'sequence' in element["fields"]:
    print("Found sequence!")
    del element['fields']['sequence']
    print(element)

Easier to read the data into a dict then traverse this and remove offending keys

import os
import json


file_name = "/tmp/jsonfile.json"
with open(file_name) as fh:
    full_data = json.load(fh)
    fh.close()

for tab in full_data['tabs']:
    for view in tab['views']:
        if view['class'] == 'DepictionScreenshotsView':
            del view['class']
        if 'screenshots' in view:
            view['screenshots'] = []

print json.dumps(full_data)

This solution creates a recursive function to iterate over the dict and remove the 'NONE's:

def del_none(obj):
    for key, value in obj.copy().items():
        if isinstance(obj[key], dict):
            obj[key] = del_none(obj[key])
        else:
            if value == 'NONE':
                del obj[key]
    return obj

Defining the original dictionary as:

original_dict = { "colo": {
  "TrBus":{
   "trade": "Test999", 
   "busCode": "NONE",
   "Trtype": "XXX",
   "sortOrder": "78654",
   "effectivedate": "NONE",
   "expirationdate": "31-DEC-9999"
  }, 
  "TrCol":{
    "Col1": "NONE",
    "Col2": "Conf"
   }
  } 
  }

And calling the function:

new_dict = del_none(original_dict)

It produces the following output:

new_dict
{'colo': {'TrBus': {'Trtype': 'XXX',
   'expirationdate': '31-DEC-9999',
   'sortOrder': '78654',
   'trade': 'Test999'},
  'TrCol': {'Col2': 'Conf'}}}

An easy solution to your problem is deleting the unwanted key in place, with del:

import json

with open('data.json') as json_data:
    data = json.load(json_data)
    for element in data: 
        del element['imageData'] 

You should add some safety checks, but you get the idea.

First question

However, whenever there's more than two elements and I enter anything higher than two, it doesn't delete anything. Even worse, when I enter the number one, it deletes everything but the zero index(whenever the array has more than two elements in it).

Inside delete_data() you have two lines reading i = + 1, which just assignes +1 (i.e., 1) to i. Thus, you're never increasing your index. You probably meant to write either i = i+1 or i += 1.

def delete_data():    # Deletes an element from the array
    view_data()
    new_data = []
    with open(filename, "r") as f:
        data = json.load(f)
        data_length = len(data) - 1
    print("Which index number would you like to delete?")
    delete_option = input(f"Select a number 0-{data_length}: ")
    i = 0
    for entry in data:
        if i == int(delete_option):
            i += 1  # <-- here
        else:
            new_data.append(entry)
            i += 1  # <-- and here

    with open(filename, "w") as f:
        json.dump(new_data, f, indent=4)

Second question: further improvements

Is there a better way to implement that in my Python script?

First, you can get rid of manually increasing i by using the builtin enumerate generator. Second, you could make your functions reusable by giving them parameters - where does the filename in your code example come from?

# view_data() should probably receive `filename` as a parameter
def view_data(filename: str):   # Prints JSON Array to screen
    with open(filename, "r") as f:
        data = json.load(f)
        # iterate over i and data simultaneously
        # alternatively, you could just remove i
        for i, item in enumerate(data):
            name = item["name"]
            chromebook = item["chromebook"]
            check_out = item["time&date"]
            print(f"Index Number: {i}")
            print(f"Name : {name}")
            print(f"Chromebook : {chromebook}")
            print(f"Time Of Checkout: {check_out} ")
            print("\n\n")
            # not needed anymore: i = i + 1

# view_data() should probably receive `filename` as a parameter
def delete_data(filename: str):    # Deletes an element from the array
    view_data()
    new_data = []
    with open(filename, "r") as f:
        data = json.load(f)
        data_length = len(data) - 1
    print("Which index number would you like to delete?")
    delete_option = input(f"Select a number 0-{data_length}: ")
    # iterate over i and data simultaneously
    for i, entry in enumerate(data):
        if i != int(delete_option):
            new_data.append(entry)

    with open(filename, "w") as f:
        json.dump(new_data, f, indent=4)

Furthermore, you could replace that for-loop by a list comprehension, which some may deem more "pythonic":

new_data = [entry for i, entry in enumerate(data) if i != int(delete_option)]

By replacing

for entry in data['Points']:

by

for entry in list(data['Points']):

you create a copy of your entries instead of iterating over them while deleting, which, in general, is a bad idea.

Use a simple filter:

no_percent = lambda feature: '%' not in feature['properties']['name']
data['features'] = filter(no_percent, data['features'])

Or as a list comprehension:

data['features'] = [feature for feature in data['features']
                      if '%' not in feature['properties']['name']]