使用str()将bytes转换为字符串后为何保留b标识与引号？

Great question! Let's break this down in plain terms:

When you use str() on a bytes object in Python, you're not actually decoding the byte sequence into human-readable text. Instead, str() returns the official string representation of the bytes object—this is exactly the output you'd see if you just typed the variable name into a Python interactive shell. The b'...' syntax is part of that representation to explicitly signal "this was originally a bytes object".

Let's walk through your example to make it clearer:

a = b'Hello World'
# Using str() gives the string description of the bytes object
b = str(a)
print(b)  # Output: b'Hello World'
type(b)  # <class 'str'>

The correct way to convert bytes to a string #

To actually turn the raw byte sequence into a proper text string, you need to decode the bytes using the appropriate character encoding (UTF-8 is the default and works for most modern text cases):

a = b'Hello World'
# Decode bytes to string (default encoding is UTF-8)
b = a.decode()
# Or explicitly specify the encoding if you need to:
# b = a.decode('utf-8')

print(b)  # Output: Hello World
type(b)  # <class 'str'>

As a quick side tip, if you ever need to convert a string back to bytes, use the encode() method on the string:

s = 'Hello World'
b = s.encode()  # Defaults to UTF-8
type(b)  # <class 'bytes'>

To wrap it up: str(bytes) gives you a string that describes the bytes object, while bytes.decode() translates the raw bytes into meaningful, human-readable text.

内容的提问来源于stack exchange，提问作者Xantium