Convert string with single quotes to json python

Two issues with answers given so far, if , for instance, one streams such non-standard JSON. Because then one might have to interpret an incoming string (not a python dictionary).

Issue 1 - demjson: With Python 3.7.+ and using conda I wasn't able to install demjson since obviosly it does not support Python >3.5 currently. So I need a solution with simpler means, for instance astand/or json.dumps.

Issue 2 - ast & json.dumps: If a JSON is both single quoted and contains a string in at least one value, which in turn contains single quotes, the only simple yet practical solution I have found is applying both:

In the following example we assume line is the incoming JSON string object :

>>> line = str({'abc':'008565','name':'xyz','description':'can control TV\'s and more'})

Step 1: convert the incoming string into a dictionary using ast.literal_eval()
Step 2: apply json.dumps to it for the reliable conversion of keys and values, but without touching the contents of values:

>>> import ast
>>> import json
>>> print(json.dumps(ast.literal_eval(line)))
{"abc": "008565", "name": "xyz", "description": "can control TV's and more"}

json.dumps alone would not do the job because it does not interpret the JSON, but only see the string. Similar for ast.literal_eval(): although it interprets correctly the JSON (dictionary), it does not convert what we need.

Sometimes, you may got this:-

data = "{'name': 'kamal', 'address': 'jb'}"

but json.loads(data) would refuse this as json require double quotes. You can use ast.literal_eval() instead.

data_dict = ast.literal_eval(data)

Related protips

convert single quote json data file to double quote json data file (without mangling inner quotes)

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JSONDecodeError: Expecting property name enclosed in double quotes: line 1 column 2 (char 1) #

The Python "JSONDecodeError: Expecting property name enclosed in double quotes: line 1 column 2 (char 1)" occurs when we try to parse an invalid JSON string (e.g. single-quoted keys or values, or a trailing comma). Use the ast.literal_eval() method to solve the error.

Here is an example of how the error occurs.

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import json

invalid_json = r"{'name': 'Alice'}"

# ⛔️ json.decoder.JSONDecodeError: Expecting property name enclosed in double quotes: line 1 column 2 (char 1)
result = json.loads(invalid_json)

Notice that the string has a single-quoted key and value, which means that it isn't a valid JSON string.

JSON (string) keys and values must be enclosed in double quotes.

Rather, it's just a Python dictionary that's wrapped in a string.

You can solve the error by using the ast.literal_eval method to evaluate the string that contains a Python literal.

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import ast

invalid_json = r"{'name': 'Alice'}"

result = ast.literal_eval(invalid_json)
print(type(result))  # 👉️ 

print(result)  # 👉️ {'name': 'Alice'}
print(result['name'])  # 👉️ Alice

The ast.literal_eval method allows us to safely evaluate a string that contains a Python literal.

The string may consist of strings, bytes, numbers, tuples, lists, dicts, sets, booleans and None.

An alternative approach is to use the str.replace() method to replace all single quotes in the string with double quotes.

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import json

invalid_json = r"{'name': 'Alice'}"

valid_json = invalid_json.replace("\'", "\"")
print(valid_json)  # 👉️ '{"name": "Alice"}'

my_dict = json.loads(valid_json)

print(my_dict)  # 👉️ {'name': 'Alice'}
print(type(my_dict))  # 👉️ 

However, this is very risky because the string could contain a single quote somewhere in its content, e.g. It's her.

You can also use the ast.literal_eval method if your string contains a trailing comma.

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import ast

invalid_json = r'{"name": "Alice",}'

result = ast.literal_eval(invalid_json)
print(type(result))  # 👉️ 

print(result)  # 👉️ {'name': 'Alice'}
print(result['name'])  # 👉️ Alice

The trailing comma also makes the string invalid JSON, but Python dictionaries are allowed to have a trailing comma after the last key-value pair.

Alternatively, you can try using the yaml.safe_load() method.

Make sure you have pyyaml installed by running pip install pyyaml.

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import yaml

invalid_json = r'{"name": "Alice",}' # 👈️ has trailing comma

my_dict = yaml.safe_load(invalid_json)

print(my_dict)  # 👉️ {'name': 'Alice'}
print(type(my_dict))  # 👉️ 

Make sure the value you are trying to parse is a JSON string and has not been already parsed into a native Python object.

If you need to parse a JSON string into a native Python object, you have to use the json.loads() method, and if you need to convert a Python object into a JSON string, you have to use the json.dumps() method.

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import json

json_str = r'{"name": "Alice", "age": 30}'


# ✅ parse JSON string to Python native dict
my_dict = json.loads(json_str)
print(type(my_dict))  # 👉️ 

# ✅ convert Python native dict to a JSON string
my_json_str = json.dumps(my_dict)
print(type(my_json_str))  # 👉️ 

The json.loads() method basically helps us load a Python native object (e.g. a dictionary or a list) from a JSON string.

The json.dumps method converts a Python object to a JSON formatted string.

The JSONEncoder class supports the following objects and types by default.

If you aren't sure what type of object a variable stores, use the built-in type() class.

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my_dict = {'name': 'Alice', 'age': 30}
print(type(my_dict))  # 👉️ 
print(isinstance(my_dict, dict))  # 👉️ True


my_str = 'hello world'
print(type(my_str))  # 👉️ 
print(isinstance(my_str, str))  # 👉️ True

The type class returns the type of an object.

The isinstance function returns True if the passed in object is an instance or a subclass of the passed in class.

Conclusion #

The Python "JSONDecodeError: Expecting property name enclosed in double quotes: line 1 column 2 (char 1)" occurs when we try to parse an invalid JSON string (e.g. single-quoted keys or values, or a trailing comma). Use the ast.literal_eval() method to solve the error.

Can I use single quotes in JSON?

How do you convert a string to a JSON object in Python?

Does JSON use double or single quotes?

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