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  • Day1_Python基础_3.Python2 or 3 ?

    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.: 

    1
    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)

    1
    2
    3
    4
    <strong>>>> a,*rest,b = range(5)
    >>> a,rest,b
    (0, [123], 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

      

    还有谁不支持PYTHON3?

    One popular module that don't yet support Python 3 is Twisted (for networking and other applications). Most

    actively maintained libraries have people working on 3.x support. For some libraries, it's more of a priority than

    others: Twisted, for example, is mostly focused on production servers, where supporting older versions of

    Python is important, let alone supporting a new version that includes major changes to the language. (Twisted is

    a prime example of a major package where porting to 3.x is far from trivial 

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  • 原文地址:https://www.cnblogs.com/wangcx/p/6688777.html
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