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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.
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’.
- For example, if you try to add an ‘
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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