What does the \'b\' character do in front of a string literal in Python?

A string is a collection of characters that can represent a single word or a complete phrase. Since you can directly assign strings in Python to a literal (unlike other technologies) it is easy to use them. The string literals are typically enclosed in quotes (' ' or " ") and they represent sequences of characters.

However, in some scenarios we will encounter a string that starts with a lowercase b for example, b'WELCOME', where the b prefix stands for bytes literal.

Bytes literals are useful when dealing with binary data, where data is transmitted or received in byte format rather than as human-readable text. In this article, we'll explore what the b character does in front of a string literal.

What is a Bytes Literal?

The string prefixed with b is not a regular string, it is a bytes object. Unlike regular strings, which represent Unicode text, the bytes object is a sequence of raw byte values ranging from 0 to 255.

Byte literals are immutable and are efficient for handling low-level binary data.

Creating Bytes Literals

Let's look at an example where we create a byte literal ?

demo = b'TutorialsPoint'
print(demo)
print(type(demo))

The output of the above code is ?

b'TutorialsPoint'
<class 'bytes'>

Strings vs Bytes Comparison

Regular strings and bytes are different types and cannot be directly compared ?

demo1 = b'Welcome'
demo2 = 'Welcome'
print(demo1 == demo2)
print(f"Type of demo1: {type(demo1)}")
print(f"Type of demo2: {type(demo2)}")

The output of the above code is ?

False
Type of demo1: <class 'bytes'>
Type of demo2: <class 'str'>

Converting Bytes to Strings

You can convert bytes to strings using the decode() method ?

demo = b'Vanakam'
result = demo.decode('utf-8')
print(result)
print(type(result))

The output of the above code is ?

Vanakam
<class 'str'>

Converting Strings to Bytes

Similarly, you can convert strings to bytes using the encode() method ?

text = "Hello World"
byte_data = text.encode('utf-8')
print(byte_data)
print(type(byte_data))

The output of the above code is ?

b'Hello World'
<class 'bytes'>

Common Use Cases

Bytes literals are commonly used in:

• File I/O operations − Reading binary files like images, videos
• Network communication − Sending data over sockets
• Cryptography − Handling encrypted data
• Data serialization − Converting objects to binary format

Conclusion

The 'b' prefix creates a bytes literal, which represents binary data as a sequence of byte values. Use bytes for binary operations and strings for text processing. Convert between them using encode() and decode() methods.