AttributeError: ‘str’ object has no attribute ‘decode’

AttributeError occurs when you try to access or set the attribute to an object that does not have it. One of the AttributeError is AttributeError: ‘str’ object has no attribute ‘decode’ error. This error occurs when we try to use the decode method on a string object because the string does not have any attribute named decode. In this short article, we will learn how we can use the decode method on a string in order to get rid of the given error. Moreover, we will also learn how to interpret errors in Python taking AttributeError: ‘str’ object has no attribute ‘decode’ as an example.

AttributeError: ‘str’ object has no attribute ‘decode’ – Possible Solutions

The string object has no attribute decode means that we are trying to apply the decode() method on the string that has already been decoded from bytes. We can get rid of the error by removing the decode() method from the string as it has already been decoded.

Let us first take an example and see why we are getting AttributeError: ‘str’ object has no attribute ‘decode’ error:

# string
my_str = 'Techfor-today'

# decoding the string
decoded = my_str.decode('utf-8')

Output:

As you can see, we got an error because we are trying to decode a string object and the error clearly says that a string object does not have any attribute decode.

Solution-1: Remove the decode method on the string

You can use the type() method to find the data type of the object and if the data type of the object is a string, you need to remove the decode method in order to get rid of the error.

In the following example, we have removed the decode() method from the string and it solved our problem.

# string
my_str = 'Techfor-today'

# decoding the string
decoded = my_str

In your program, please check if you are using the decode method on any string value, then you need to remove it.

Solution-2: Encoding string and decoding bytes

You need to first use the encoding method in order to convert a string into bytes and then you can use the decoding method on bytes to convert it back into the string.

In the following example, we will first convert a string into a byte object using the encoding method as shown below:

# string
my_str = 'Techfor-today'

# encoded the string
encoded = my_str.encode('utf-8')

# print
print(encoded)
print(type(encoded))

Output:

b'Techfor-today'
<class 'bytes'>

As you can see, the encode() method has converted the string object into a byte object. Now, we can apply the decode() method on the byte object to get the string back as shown below:

# string
my_str = 'Techfor-today'

# encoded the string
encoded = my_str.encode('utf-8')

# decoding
decoded = encoded.decode('utf-8')

# print
print(decoded)
print(type(decoded))

Output:

Techfor-today
<class 'str'>

Notice that now, the data type of the object is again string as we decoded the byte object.

Solution-3: Converting a string into bytes

As we know that the error occurs because the string object does not have the decode() attribute. This means that we are applying the correct method to the wrong data type. In order to decode the object, we need to convert it into a byte object.

The following will give you an error as the object is a string type, not a byte type.

# string
my_str = 'Techfor-today'

decoded = my_str.decode('utf-8')

# print
print(decoded)
print(type(decoded))

Output:

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
/tmp/ipykernel_358845/2443300749.py in <module>
      2 my_str = 'Techfor-today'
      3 
----> 4 decoded = my_str.decode('utf-8')
      5 
      6 # print

AttributeError: 'str' object has no attribute 'decode'

As you can see, we got an error because the data type of the object was the string.

There are various methods in order to convert a string object into bytes. One of the popular methods is using the bytes() method which takes the string and returns the bytes. See the example below:

# string
my_str = 'Techfor-today'

# decode method on byte
decoded = bytes(my_str, 'utf-8').decode('utf-8')

As you can see, we used the bytes() method on the string which converted the string into bytes, and then we applied the decode method on the bytes of the string.

Another method to convert the string into bytes is to put the b before the string as shown below:

# string
my_str = b'Techfor-today'

# decode method on byte
decoded = my_str.decode('utf-8')

The b alphabet before the string indicates that the object is going to be bytes.

Solution-4: Using try-except block

The try and except blocks in Python are used to handle errors in Python. The code inside the try block will be executed first and if any error occurs then instead of crashing the script, the code inside the except block will be executed.

Let us take an example, and see how we can use the try-except block in order to solve the error:

# string
my_str = 'Techfor-today'

try:
    # decode method on byte
    decoded = my_str.decode('utf-8')

except:
    print("There is an error in the try block")

Output:

There is an error in the try block

As you can see, we got the message that says that there has been an error in the try block without crashing the code.

Solution-5: Using an if-else statement

When you are not sure whether the data type is going to be string or byte, then you can use the if statement in order to check the type of the object.

The sample example shows how we can use the if statement to check the type of the object before decoding it.

# string
my_str = 'Techfor-today'

if isinstance(my_str, bytes):
    # decode method on byte
    decoded = my_str.decode('utf-8')

else:
    print("The object is not of bytes")

Output:

The object is not of bytes

Notice that because the type of the object was not bytes, the else statement was executed.

Understanding the AttributeError: ‘str’ object has no attribute ‘decode’ Error

As you can see, the error has two major parts which help us to figure out the problem. The first part of the error represents the category of the error which in our case is the AttributeError. The attribute error means we are trying to apply a method on an object that does not support it. The second part of the error helps us to figure out which method raises the attribute error. In our case, it clearly says that the string object does not have a decode attribute which means we are applying the decode method on the string data type somewhere in our program.

What is encoding in Python?

The encoding in Python is a method that helps us to convert the string object into bytes. We can use the encode() method in Python which converts the string into bytes. See the following examples:

# string
my_str = 'Techfor-today'

# using encoding method
encoded = my_str.encode()

# printing
print(type(my_str))
print(type(encoded))

Output:

<class 'str'>
<class 'bytes'>

As you can see, the string object was converted into bytes by the encoded method.

What is decoding in Python?

The decoding method in Python converts the bytes object back into a string object. The decode() method in Python helps us to convert the bytes into a string object.

Here is an example of how we can use the decode method on a byte object:

# string
my_str = b'Techfor-today'

# using encoding method
decoded = my_str.decode()

# printing
print(type(my_str))
print(type(decoded))

Output:

<class 'bytes'>
<class 'str'>

As you can see, the bytes object was converted into a string object using the decode method.

Summary

In this short article, we discussed how we can solve the AttributeError: ‘str’ object has no attribute ‘decode’ Error. The error occurs when we try to apply the decode method on a string object which does not have the decode attribute.

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