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二、Python发展史
三、Python 2 or 3?
系统位数 32位与64位的区别
32bit =内存的最大寻址空间是2**32， 4GB
64bit, =2**64 但实际上支持不到这莫大的内存，2**4x, 目前主板支持的最大的内存是100多GB
4gb ==64位系统 会不会比32位系统快？ = 一样的
http://jingyan.baidu.com/article/215817f7c772991edb142374.html
CPU—内存—硬盘速度比拼
硬盘：
5400转 = 每分钟 =骑自行车
7200转 = 每分钟 =骑电动车
10000转 = 每分钟 =骑快速电动车
15000转 = 每分钟 =骑摩托车 机械硬盘最快的
SSD硬盘 = Tesla
总结: In summary : Python 2.x is legacy, Python 3.x is the present and future of the language
(python2.x是遗产，python3.x是现在和未来的语言),意思就是我们要学就得学未来的语言，而不是去学遗产
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).
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原文地址：http://www.cnblogs.com/tiger666/p/5789661.html
