显然，以下是有效的语法:
b'The string'
我想知道:
字符串前面的b是什么意思? 使用它的效果是什么? 在什么情况下使用它比较合适?
我在SO上找到了一个相关的问题，但这个问题是关于PHP的，它指出b是用来表示字符串是二进制的，而不是Unicode，这是需要代码从PHP < 6版本兼容，当迁移到PHP 6时。我不认为这适用于Python。
我确实在Python网站上找到了这个文档，是关于使用u字符以相同的语法指定字符串作为Unicode的。不幸的是，该文档中没有任何地方提到b字符。
另外，出于好奇，除了b和u还有别的符号吗?
当前回答
b"hello" is not a string (even though it looks like one), but a byte sequence. It is a sequence of 5 numbers, which, if you mapped them to a character table, would look like h e l l o. However the value itself is not a string, Python just has a convenient syntax for defining byte sequences using text characters rather than the numbers itself. This saves you some typing, and also often byte sequences are meant to be interpreted as characters. However, this is not always the case - for example, reading a JPG file will produce a sequence of nonsense letters inside b"..." because JPGs have a non-text structure.
.encode()和.decode()在字符串和字节之间转换。
其他回答
b表示字节字符串。
字节是实际的数据。字符串是一种抽象。
如果你有一个多字符的字符串对象，你取一个字符，它将是一个字符串，它的大小可能超过1字节，这取决于编码。
如果使用字节字符串的1个字节，您将得到一个从0-255的8位值，如果这些字符由于编码是> 1字节，那么它可能不代表一个完整的字符。
TBH我会使用字符串，除非我有一些特定的低级别的理由使用字节。
您可以使用JSON将其转换为字典
import json
data = b'{"key":"value"}'
print(json.loads(data))
{“关键”:“价值”}
瓶:
这是一个flask的例子。在终端行上运行:
import requests
requests.post(url='http://localhost(example)/',json={'key':'value'})
瓶/ routes.py
@app.route('/', methods=['POST'])
def api_script_add():
print(request.data) # --> b'{"hi":"Hello"}'
print(json.loads(request.data))
return json.loads(request.data)
{“关键”:“价值”}
b"hello" is not a string (even though it looks like one), but a byte sequence. It is a sequence of 5 numbers, which, if you mapped them to a character table, would look like h e l l o. However the value itself is not a string, Python just has a convenient syntax for defining byte sequences using text characters rather than the numbers itself. This saves you some typing, and also often byte sequences are meant to be interpreted as characters. However, this is not always the case - for example, reading a JPG file will produce a sequence of nonsense letters inside b"..." because JPGs have a non-text structure.
.encode()和.decode()在字符串和字节之间转换。
问题的答案是:
data.encode()
为了解码它(去掉b，因为有时候你不需要它)
use:
data.decode()
下面是一个例子，在Python 3.x中，缺少b将抛出TypeError异常
>>> f=open("new", "wb")
>>> f.write("Hello Python!")
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: 'str' does not support the buffer interface
加上一个b前缀就能解决这个问题。
