[Python] Converting String Type Objects To Correct Types!

I was writing custom template tags for one of my Django package. I came across a situation where I had lists in string format. I need to convert them into lists.

temp_str = '[345, 3, 456, 45]'
required_obj = [345, 3, 456, 45]

There are two methods to get this job done.

1. ast.literal_eval:

This can be used to evaluate strings containing Python values from untrusted sources without parsing values.

import ast
ast.literal_eval(temp_str)

2. json.loads:

This is used to deserialize a string to python object using a conversion table.

import json
json.loads(temp_str)

These two functions come in handy whenever you want to convert a list of python objects to their correct types. For example, if you have list of python objects like this

obj_list =  ['hello', '3', '3.64', '-1']

You can convert them to their corresponding types using these functions.

def converter(l):
    for i in l:
        try:
            yield json.loads(i)
        except ValueError:
            yield i

def converter(l):
    for i in l:
        try:
            yield ast.literal_eval(i)
        except ValueError:
            yield i

They yield a objects of corresponding types

new_obj_list = ['hello', 3, 3.64, -1]

References: Python Docs, Stackoverflow

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