[Solved] TypeError: a bytes-like object is required, not ‘str’

TypeError: a bytes-like object is required, not ‘str’ error occurs when you tried to apply a function to the value that does not support that function. An example could be trying to iterate over a number because a number cannot be iterated. In this short article, we will learn how we can solve TypeError: a bytes-like object is required, not ‘str’ error using different methods. Moreover, we will discuss the reasons for getting this error which will help you to easily solve the problem.

TypeError: a bytes-like object is required, not ‘str’

TypeError: a bytes-like object is required, not ‘str’ error occurs when we tried to apply a function that does not support it. The error clearly tells us that we have tried to access an object as if it was a string when we should be accessing it as a list of bytes.

This error usually occurs when dealing with text files. When we open the file in Python, we store it in the list of bytes but when we tried to print we get this error.

For example, let us assume that we have a text file that we want to open using Python and print some words from it:

# opening the file
with open("file.txt", "rb") as file:
	name = file.readlines()

# checking if name is in the file
for i in name:
    if "Bashir" in i:
        print(i)

Output:

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
/tmp/ipykernel_287007/2787749345.py in <module>
      5 # checking if name is in the file
      6 for i in name:
----> 7     if "Bashir" in i:
      8         print(i)
      9 

TypeError: a bytes-like object is required, not 'str'

As you can see, we get the error when we run the code. The reason for getting this error is that the data is stored in the form of bytes in the variable name, and we treated it as a list or iterable.

Solution-1: Using encode() method

We can solve the error using the encode() method. This method will encode the strings into bytes.

Here is an example of how we can use this method to solve TypeError: a bytes-like object is required, not ‘str’ error:

# opening the file
with open("file.txt", "rb") as file:
	name = file.readlines()

# checking if name is in the file
for i in name:
    
    # checking the name
    if 'Bashir'.encode('utf-8') in i:  
        print("Name exists in the file")

Output:

Name exists in the file

As you can see, the code successfully runs without giving any errors.

Solution-2: Using the decode method

We can also, decode the byte object into a string as well:

# opening the file
with open("file.txt", "rb") as file:
	name = file.readlines()

# checking if name is in the file
for i in name:
    
    # checking the name
    if 'Bashir' in i.decode('utf-8'):  
        print("Name exists in the file")

Output:

Name exists in the file

As you can see, the code runs without any error:

Solution-3: Typecast byte to string

We can encode the string into bytes to get rid of TypeError: a bytes-like object is required, not ‘str’ error. For example, let us assume that we have the following code:

# defining string
a=("This is Bashir").encode()

# defining substring
b=("Bashir")

# using if statement
if b in str(a):
  print("Sub String exists")

Output:

Sub String exists

As you can see, we didn’t get the error anymore.

Solution-4: Type cast string to byte

As we did above, we can also convert strings to bytes. In this example, we will convert the string into bytes which will solve the problem:

# defining a string
a=("This is Bashir").encode()

# type casting- converted string to byte
b=bytes("Bashir","utf-8")

# using if statement
if b in a:
  print("Sub String exists")

Output:

Sub String exists

As you can see, we solve the error by converting the string into bytes.

Solution-5: Alternative method to convert string to byte

Here is an alternative method to convert string to byte.

# defining string
a = (b"This is Bashir")

# printing type
print(type(a))

Output:

<class 'bytes'>

As you can see, the type is byte rather then string.

Understanding the TypeError: a bytes-like object is required, not ‘str’

Let us explore what kind of information we can get from Python errors: There are two parts of the error in Python. The first part of the error represents the category of the error which in this case is the TypeError. The second part of the error gives more specific information about the error for example in this case it says a bytes-like object is required, not str.

What is TypeError in Python?

The TypeError means we are applying some function on wrong. The Python TypeError is an exception that occurs when the data type of an object in an operation is inappropriate. This can happen when an operation is performed on an object of an incorrect type, or it is not supported for the object

What is a byte in Python?

Python bytes() We utilize the Python bytes() method to manipulate binary data in the program. The byte is a digital information unit that typically consists of 8 bits each of which consists of a 0 or 1. A byte is a computer architecture term for memory storage that encodes a single character of text in a computer

What is String in Python?

Like many other popular programming languages, strings in Python are arrays of bytes representing Unicode characters. However, Python does not have a character data type, a single character is simply a string with a length of 1. Square brackets can be used to access elements of the string.

Reasons for getting TypeError: a bytes-like object is required, not ‘str’ error

There can be several reasons for getting TypeError: a bytes-like object is required, not ‘str’ error: Some of the main reasons are:

• When you are trying to treat a string file that is opened as in a binary model.
• When you pass a string to a function that accepts only bytes.
• When you are trying to add a string with byte-like objects

Summary

In this short article, we discussed how we can solve TypeError: a bytes-like object is required, not ‘str’ error. We discussed five different methods to solve the error Moreover, we also discussed the reasons for getting TypeError: a bytes-like object is required, not ‘str’ error.

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