Python 3字节格式化

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有趣的是，.format()似乎不支持字节序列; 正如您已经演示的那样。

您可以按照这里的建议使用 .join(): http://bugs.python.org/issue3982

b", ".join([b'1', b'2', b'3'])

与使用 .format()相比，与 .join()相关的速度优势由 BDFL 自己显示: http://bugs.python.org/msg180449

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另一种方式是:

"{0}, {1}, {2}".format(1, 2, 3).encode()

在 IPython1.1.0和 Python3.2.3上进行了测试

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最佳答案

从 Python 3.5开始，%格式化也适用于 bytes！

这是 PEP 461的一部分，作者是 Ethan Furman:

PEP: 461
Title: Adding % formatting to bytes and bytearray
Version: $Revision$
Last-Modified: $Date$
Author: Ethan Furman <ethan at stoneleaf.us>
Status: Draft
Type: Standards Track
Content-Type: text/x-rst
Created: 2014-01-13
Python-Version: 3.5
Post-History: 2014-01-14, 2014-01-15, 2014-01-17, 2014-02-22, 2014-03-25,
2014-03-27
Resolution:




Abstract
========


This PEP proposes adding % formatting operations similar to Python 2's ``str``
type to ``bytes`` and ``bytearray`` [1]_ [2]_.




Rationale
=========


While interpolation is usually thought of as a string operation, there are
cases where interpolation on ``bytes`` or ``bytearrays`` make sense, and the
work needed to make up for this missing functionality detracts from the overall
readability of the code.




Motivation
==========


With Python 3 and the split between ``str`` and ``bytes``, one small but
important area of programming became slightly more difficult, and much more
painful -- wire format protocols [3]_.


This area of programming is characterized by a mixture of binary data and
ASCII compatible segments of text (aka ASCII-encoded text).  Bringing back a
restricted %-interpolation for ``bytes`` and ``bytearray`` will aid both in
writing new wire format code, and in porting Python 2 wire format code.


Common use-cases include ``dbf`` and ``pdf`` file formats, ``email``
formats, and ``FTP`` and ``HTTP`` communications, among many others.

PEP 461是吉多·范罗苏姆于二○一四年三月二十七日接纳:

接受，恭喜你又组织了一场争论讨论，忍受我最后一分钟的愚蠢！

由此，我们可以明显地得出结论，%不再计划弃用(正如 Python 3.1所宣布的那样)。

小开

我发现 %b在 Python 3.6.2中工作得最好，它应该可以同时适用于 b“”和“”:

print(b"Some stuff %b. Some other stuff" % my_byte_or_unicode_string)

小开

我已经找到了这个工作。

a = "{0}, {1}, {2}".format(1, 2, 3)


b = bytes(a, encoding="ascii")


>>> b
b'1, 2, 3'

小开

对于 Python 3.6 + ，您可以使用这种漂亮而干净的语法:

f'foo {bar}'.encode() # a byte string