[Solved] TypeError: A Bytes-Like object Is Required, not ‘str’

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Introduction

Objective: In this tutorial, our goal is to fix the following exception TypeError: A Bytes-Like object Is Required, not ‘str’ and also discuss similar exceptions along with their solutions.

Example: Consider the following file ‘scores.txt’which contains scores of some random candidates.

scoresDownload file

Now, let us try to access the score obtained by Ravi from the file with the help of a simple program.

with open("scores.txt","rb") as p:
    lines = p.readlines()
for line in lines:
    string=line.split('-')
    if 'Ravi' in string[0]:
        print('Marks obtained by Ravi:',string[1].strip())

Output:

Traceback (most recent call last):
  File "main.py", line 4, in <module>
    string=line.split('-')
TypeError: a bytes-like object is required, not 'str'

Explanation:

As you can see, we got an exception TypeError: a bytes-like object is required, not ‘str’ since we tried to split a ‘bytes’ object using a separator of ‘str’ type.

Thus to fix our problem, first of all let us understand what TypeError is?

? What is TypeError in Python?

TypeError is one of the most commonly faced problem by Python programmers.

  • It is raised whenever you use an incorrect or unsupported object type in a program.
  • It is also raised if you try to call a non-callable object or if you iterate through a non iterative identifier.
    • For example, if you try to add an ‘int’ object with ‘str’.

Example:

a = 1
b = 2
c = 'Three'
print(a + b + c)  # Trying to add 'int' objects with 'str'

Output:

Traceback (most recent call last):
  File "main.py", line 4, in <module>
    print(a + b + c)  # Trying to add 'int' objects with 'str'
TypeError: unsupported operand type(s) for +: 'int' and 'str'

Solution: To fix the above problem, you can either provide an ‘int’ object to variable c or you can typecast variable a and b to ‘str’ type.

a = 1
b = 2
c = 3  # error fixed by using int object
print(a + b + c)

# Output: 6

Since we now have an idea about TypeErrors in Python, let us discuss – what is TypeError: A Bytes-Like object Is Required, not ‘str’ ?

? What is TypeError: A Bytes-Like object Is Required, not ‘str’ ?

TypeError: A Bytes-Like object Is Required, not ‘str’ is raised when you try to use a ‘str’ object in an operation which supports only ‘bytes’ object.

Therefore when you have a look at the above example that involves extracting data from ‘scores.txt’, we are trying to use ‘str’ to split a byte object which is an unsupported operation. Thus, Python raises the TypeError.

❖ How to Fix TypeError: a bytes-like object is required, not ‘str’ ?

There are numerous solutions to solve the above exception. You can use choose whichever seems more suitable for your program. Let’s dive into them one by one.

?️ Solution 1: Replacing ‘rb’ with ‘rt’

You can simply change the mode from ‘rb’ i.e. read-only binary to ‘rt’ i.e. read-only text. You can even use ‘r’ that means read-only mode which is the default mode for open().

with open("scores.txt", "rt") as p:  # using rt instead of rb
    lines = p.readlines()
for line in lines:
    string = line.split('-')
    if 'Ravi' in string[0]:
        print('Marks obtained by Ravi:', string[1].strip())

Output:

Marks obtained by Ravi: 65

Thus, once the file is opened in text mode, you no longer have to deal with a byte object and easily work with strings.

?️ Solution 2: Adding prefix ‘b‘

You can simply add prefix ‘b’ before the delimiter within the split() method. This prefix ensures that you can work upon a byte object.

with open("scores.txt", "rb") as p:  # using prefix b
    lines = p.readlines()
for line in lines:
    string = line.split(b'-')
    if b'Ravi' in string[0]:
        print('Marks obtained by Ravi:', string[1].strip())

Output:

Marks obtained by Ravi: b'65'

?️ Solution 3: Using decode() Method

❖ decode() is a Python method that converts one encoding scheme, in which the argument string is encoded to another desired encoding scheme. The decode() method by default takes the encoding scheme as ‘utf-8’ when no encoding arguments are given.

Thus, you can use the decode() method to decode or convert an object of  ‘bytes’ type to ‘str’ type.

with open("scores.txt", "rb") as p:
    lines = [x.decode() for x in p.readlines()]  # applying decode()
for line in lines:
    string = line.split('-')  # no exception raised because line is of 'str' type
    if 'Ravi' in string[0]:
        print('Marks obtained by Ravi:', string[1].strip())

Output:

Marks obtained by Ravi: 65

?️ Solution 4: Using encode() Method

Just like the decode() method, we can use the encode() method for fixing the same problem.

with open("scores.txt", "rb") as p:
    lines = p.readlines()
for line in lines:
    string = line.split('-'.encode())  # encode converts ‘str’ to ‘bytes’
    if 'Ravi'.encode() in string[0]:
        print('Marks obtained by Ravi:', string[1].strip())

Output:

Marks obtained by Ravi: b'65'

Recommended Article: Python Unicode Encode Error

?️ Solution 5: Using bytes() Method

bytes() is a method in Python, that can be used to convert a given string to ‘bytes’ type. You need to provide the string to be converted as source and the encoding which in this case is ‘utf-8’ as arguments to the method.

Let’s apply the bytes() method to solve our problem.

with open("scores.txt", "rb") as p:
    lines = p.readlines()
for line in lines:
    string = line.split(bytes('-', 'utf-8'))  # converts str to bytes
    if bytes('Ravi', 'utf-8') in string[0]:
        print('Marks obtained by Ravi:', string[1].strip())

Output:

Marks obtained by Ravi: b'65'

❖ Note: UTF-8 is a byte encoding used to encode Unicode characters.

?️ Solution 6: Using a List Comprehension and str() Method

Another workaround to solve our problem is to be use the str() method within a list comprehension. This allows you to typecast the bytes object to str type.

with open("scores.txt", "rb") as p:
    lines = [str(x) for x in p.readlines()]  # using str() to typecast bytes to str
for line in lines:
    my_string = line.split('-')
    if 'Ravi' in my_string[0]:
        print('Marks obtained by Ravi:', my_string[1].strip(" '"))

Output:

Marks obtained by Ravi: 65

Conclusion

Let us now recall the key points discussed in this tutorial:

  • What is TypeError in Python?
  • What is TypeError: A Bytes-Like object Is Required, not ‘str’ ?
  • How to fix TypeError: a bytes-like object is required, not ‘str’ ?

Please subscribe and stay tuned for more interesting discussions in the future. Happy coding! ?

Authors:
?‍? Shubham Sayon
?‍? Anirban Chatterjee

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