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

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.

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))  # 👉️ <class 'dict'>

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.

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))  # 👉️ <class 'dict'>

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))  # 👉️ <class 'dict'>

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))  # 👉️ <class '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.

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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))  # 👉️ <class 'dict'>

# ✅ convert Python native dict to a JSON string
my_json_str = json.dumps(my_dict)
print(type(my_json_str))  # 👉️ <class '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))  # 👉️ <class 'dict'>
print(isinstance(my_dict, dict))  # 👉️ True


my_str = 'hello world'
print(type(my_str))  # 👉️ <class '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.