为什么python np数组输出中有更多字符串？

Question

我不明白为什么下面的代码答案是：

import numpy as np
dt=[('name','S16'),('grad',int),('cpg',float)]
val=[("Ahmadmm",2008,12),('ali',2010,12.2),('mitra',505,15.15)]
arr=np.array(val,dtype=dt)
print(arr)

output:  [(b'Ahmadmm', 2008, 12.  ) (b'ali', 2010, 12.2 ) (b'mitra',  505, 15.15)]

为什么每个字符串前都有一个“b”

Answer 1

正如NPE在本question中所述，引用Python 2.x documentation：

A prefix of 'b' or 'B' is ignored in Python 2; it indicates that the literal should become a bytes literal in Python 3 (e.g. when code is automatically converted with 2to3). A 'u' or 'b' prefix may be followed by an 'r' prefix.

报告指出：

Bytes literals are always prefixed with 'b' or 'B'; they produce an instance of the bytes type instead of the str type. They may only contain ASCII characters; bytes with a numeric value of 128 or greater must be expressed with escapes.

Answer 2

我想这篇文章回答了你的问题：What does the 'b' character do in front of a string literal?。“b”字符基本上表示字节文字