How can I call .format() from a dictionary when I can only access the string values of that dictiona-CodePudding

I have a program where the user uploads a JSON file and then the program turns it into a dictionary and then does some math on it. Before that math I want to access items of the dictionary within the actual dictionary. Essentially this would be a popup message that says something along the lines of "The values uploaded from the JSON file are x, y, and z".

   example_dict = {
        "first_item": 11,
        "second_item": "this is a sentence",
        "message_item": "'Second item was {}, and the first item is {}'.format(example_dict['second_item'], example_dict['first_item])"
    }

print(example_dict)

I already have the uploading from a JSON part working, this is an example of what I would like to have happen.

Yes I am aware that I can update the dictionary values from outside of it, but, at the end, I have to rewrite the dictionary back to the JSON file, so I am essentially then hard coding it. Whatever is in that dictionary is rewritten. For example I could do,

message = "Second item was {}, and the first item is {}".format(example_dict['second_item'], example_dict['first_item'])
example_dict['message_item'] = message

This the means that, if the user wants to edit the JSON file to have it only show the first value, they cannot do that.

CodePudding user response：

You can use eval or exec functions in python to execute arbitrary python code.

example_dict = {
        "first_item": 11,
        "second_item": "this is a sentence",
        "message_item": "'Second item was {}, and the first item is {}'.format(example_dict['second_item'], example_dict['first_item])"
    }

message = eval(example_dict['message_item'])
print(message)

CodePudding user response：

I was able to get my desired output using the .format(**dictionary) method. I found it in another question and was able to tweak it to make it work for my specific use case. Working code below.

example_dict = {
    "first_item": 11,
    "second_item": "this is a sentence",
    "message_item": "Second item was {second_item}, and the first item is {first_item}"
}


message = example_dict['message_item'].format(**example_dict)
print(message)