What is the Purpose of the \'b\' Prefix in Python Strings?

Understanding the Mysterious 'b' Prefix in Python Strings

Python offers various prefixes to define different types of strings, such as Unicode strings (u) and raw strings (r). But what does a preceding 'b' signify?

Decoding the 'b' Prefix

The 'b' prefix denotes a bytes string literal. When encountered in Python 3 code, it signifies a bytes object, unlike regular Unicode strings. It also serves as a representation for bytes objects when displayed in the Python shell or containers.

Characteristics of Bytes Strings

Bytes objects consist of a sequence of integers within the range 0-255. Python displays them as ASCII codepoints for ease of reading. However, bytes outside the printable ASCII range are presented as escape sequences.

Construction and Modification of Bytes Strings

Bytes objects can be constructed from any sequence of integers in the 0-255 interval, such as lists. Indexing retrieves integers, while slicing creates new bytes objects.

Distinction from Text Strings

Bytes represent binary data, including encoded text. To extract text, the bytes object must be decoded using the appropriate codec (e.g., UTF-8). Conversely, encoding is utilized to convert text strings into bytes.

Compatibility in Python 2

Python 2 versions 2.6 and 2.7 allow for the creation of string literals using the 'b'..' syntax to facilitate code compatibility with both Python 2 and 3.

Immutability and Bytearrays

Bytes objects, like strings, are immutable. For mutable bytes values, consider using bytearray() objects.

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