TypeError: decoding str is not supported in Python [Solved]

# TypeError: decoding str is not supported in Python

The Python "TypeError: decoding str is not supported" occurs when we try to convert an object to a string multiple times or set the encoding keyword argument in our call to the str() class without providing a bytes object.

Here is an example of how the error occurs.

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# ⛔️ TypeError: decoding str is not supported
str('hello', str(123))

The code sample has two calls to the str class, one nested inside the other.

Here is another example.

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# ⛔️ TypeError: decoding str is not supported
str('abc', encoding='utf-8')

In the second example, we set the encoding keyword argument without providing a valid bytes object.

# Make sure to supply a valid bytes object

We can only set the encoding when passing a valid bytes object.

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print(str(b'abc', encoding='utf-8')) # 👉️ "abc"

If you need to concatenate strings, use the addition (+) operator.

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print('abc' + str(123))  # 👉️ "abc123"

The addition (+) operator can be used to concatenate strings.

Alternatively, you can use a formatted string literal.

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str_1 = 'abc'

num_1 = 123

result = f'{str_1} {num_1}'

print(result)  # 👉️ 'abc 123'

Make sure to wrap expressions in curly braces - {expression}.

# You don't have to decode strings

The "TypeError: decoding str is not supported" error message means that we are somehow trying to decode a string.

Here is a simple example of encoding a string to bytes and decoding the bytes object back to a string.

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my_bytes = 'hello world'.encode('utf-8')
print(my_bytes)  # 👉️ b'hello world'

my_str = my_bytes.decode('utf-8')
print(my_str)  # 👉️ "hello world"

The str.encode() method returns an encoded version of the string as a bytes object. The default encoding is utf-8.

The bytes.decode() method returns a string decoded from the given bytes. The default encoding is utf-8.

Decoding is the process of converting a bytes object to a string and since we already have a string, we don't have to call the decode() method on it.

# Additional Resources

You can learn more about the related topics by checking out the following tutorials:

• LookupError: unknown encoding in Python [Solved]
• AttributeError: 'str' object has no attribute 'decode'
• TypeError: string argument without an encoding in Python
• TypeError: Strings must be encoded before hashing (Python)