Day1_Python基础_3.Python2 or 3 ?

最新推荐文章于 2022-02-05 21:00:01 发布

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最新推荐文章于 2022-02-05 21:00:01 发布

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原文链接：http://www.cnblogs.com/wangcx/p/6688777.html

本文总结了Python2与Python3的主要区别，并推荐开发者选择Python3。Python3自2008年发布以来，已获得长期稳定发展，拥有更好的Unicode支持及更简洁的语言特性。核心改进包括PRINT成为函数、所有字符串默认为Unicode等。

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三、Python 2 or 3?

结论：请选择Python3

In summary : Python 2.x is legacy, Python 3.x is the present and future of the language

Python 3.0 was released in 2008. The final 2.x version 2.7 release came out in mid-2010, with a statement of

extended support for this end-of-life release. The 2.x branch will see no new major releases after that. 3.x is

under active development and has already seen over five years of stable releases, including version 3.3 in 2012,

3.4 in 2014, and 3.5 in 2015. This means that all recent standard library improvements, for example, are only

available by default in Python 3.x.

Guido van Rossum (the original creator of the Python language) decided to clean up Python 2.x properly, with less regard for backwards compatibility than is the case for new releases in the 2.x range. The most drastic improvement is the better Unicode support (with all text strings being Unicode by default) as well as saner bytes/Unicode separation.

Besides, several aspects of the core language (such as print and exec being statements, integers using floor division) have been adjusted to be easier for newcomers to learn and to be more consistent with the rest of the language, and old cruft has been removed (for example, all classes are now new-style, "range()" returns a memory efficient iterable, not a list as in 2.x).

py2与3的详细区别

PRINT IS A FUNCTION

The statement has been replaced with a print() function, with keyword arguments to replace most of the special syntax of the old statement (PEP 3105). Examples:

You can also customize the separator between items, e.g.:

 
          
                print
                (
                "There are <"
                , 
                2
                *
                *
                32
                , 
                "> possibilities!"
                , sep
                =
                "")
               

         

ALL IS UNICODE NOW

从此不再为讨厌的字符编码而烦恼

还可以这样玩： (A,*REST,B)=RANGE(5)

 
                
                      <strong>>>> a,
                      *
                      rest,b 
                      = 
                      range
                      (
                      5
                      )
                     

                      >>> a,rest,b
                     

                      (
                      0
                      , [
                      1
                      , 
                      2
                      , 
                      3
                      ], 
                      4
                      )
                     

                      <
                      /
                      strong>
                     

               

某些库改名了

Old Name	New Name
_winreg	winreg
ConfigParser	configparser
copy_reg	copyreg
Queue	queue
SocketServer	socketserver
markupbase	_markupbase
repr	reprlib
test.test_support	test.support