高清完整Python3.2.3官方PDF文档

Python3.2.3官方文档（中文版） 由笔者自己翻译 学习Python 2还是Python 3？
罗振宇在今年的跨年演讲，《时间的朋友》中有个观点，大意是说，人们都有一种受虐情节，有时候希望别人对他粗暴一点。为此，他还举了两个例子，分别是“乔布斯对待消费者的态度”和“和菜头不尊重他的饮食需求”，末了还很享受的来一句：我爱死他了，对我再粗暴一点好不好！
看到很多新同学在学习Python的过程中，犹豫学习Python 2还是学习Python 3而迟迟不行动，白白地浪费了大把时间，错过了升职加薪的机会，我真心觉得非常遗憾。所以，我忍不住想对大家粗暴一次，给大家一个粗暴而又正确的答案：
应该学习Python 2还是Python 3？
都要学！
这个答案可能很出乎意料，也很容易反驳，例如：
Python 3 才是Python的未来
Python 官方都建议指直接学习Python 3
Python 2 只维护到2020年
真的是这样吗？作为一个在一线互联网公司奋斗的工程师，也是一个多年的Python老手，大家不妨来看看我这么说的理由。

高清完整Python3.2.3官方PDF文档介绍

目录
第一章Python初步介绍.
1.1Python用作计算器
1.1.1数字.
1.12字符串
1.1.3列表.
1.2初步走进编程之门.
第二章更多控制流程语句.
21if语句
2.2 for语句
23 range0方法.
2.4 break和continue语句和在循环中的else子旬
2.5 Pass语句.
2.6定义方法..
2.7更多关于方法定义
2.71默认参数值.
2.7.2关键字参数.
2.7.3可变参数列表
2.7.4拆分参数列表
2.7.5形式
2.7.6文档字符串
2.8编码风格.
第三章数据结构...
3.1列表
3.1.1把列表当做栈来用.
3.12把列表当做队列来用.
3.1.3递推式构造列表.
3.1.4嵌套列表推导式.
3.3元組和序列.
3.4 Set集合.

高清完整Python3.2.3官方PDF文档特色

1）Python 3 取胜：
Now, in 2018, it’s more of a no-brainer: Python 3 is the clear winner for new learners or those wanting to update tudemheir skills. Here, we’ll cover why Python 3 is better, and why companies have been moving from Python 2 to 3 en masse.
2）python2和3发展历史：
Python 2.0 was first released in 2000. Its latest version, 2.7, was released in 2010.
Python 3.0 was released in 2008. Its newest version, 3.6, was released in 2016, and version 3.7 is currently in development.
Although Python 2.7 is still widely used, Python 3 adoption is growing quickly. In 2016, 71.9% of projects used Python 2.7, but by 2017, it had fallen to 63.7%. This signals that the programming community is turning to Python 3–albeit gradually–when developing real-world applications.
Notably, on January 1, 2018, Python 2.7 will “retire” and no longer be maintained. (The clock is literally ticking!)
这个时间线很有意思。
3）python2和3的主要区别：
PYTHON 2 IS LEGACY, PYTHON 3 IS THE FUTURE. 因为python2即将被放弃维护。所以python2即将成为过去式（legacy）是显而易见的。
PYTHON 2 AND PYTHON 3 HAVE DIFFERENT (SOMETIMES INCOMPATIBLE) LIBRARIES
二者支持的库不一样，而且转换起来也比较麻烦（complicated）
THERE IS BETTER UNICODE SUPPORT IN PYTHON 3
In Python 3, text strings are Unicode by default. In Python 2, strings are stored as ASCII by default–you have to add a “u” if you want to store strings as Unicode in Python 2.x.

This is important because Unicode is more versatile than ASCII. Unicode strings can store foreign language letters, Roman letters and numerals, symbols, emojis, etc., offering you more choices.
PYTHON 3 HAS IMPROVED INTEGER DIVISION:
In Python 2, if you write a number without any digits after the decimal point, it rounds your calculation down to the nearest whole number.

For example, if you’re trying to perform the calculation 5 divided by 2, and you type 5 / 2, the result will be 2 due to rounding. You would have to write it as 5.0 / 2.0 to get the exact answer of 2.5.

However, in Python 3, the expression 5 / 2 will return the expected result of 2.5 without having to worry about adding those extra zeroes.

This is one example of how Python 3 syntax can be more intuitive, making it easier for newcomers to learn Python programming.
THE TWO VERSIONS HAVE DIFFERENT PRINT STATEMENT SYNTAXES
This is only a syntactical difference–and some may consider it trivial–so it doesn’t affect the functionality of Python. That said, it is still a big and visible difference you should know about.

Essentially, in Python 3, the print statement has been replaced with a print () function.
4）为什么公司会选择从python2转到python3
As mentioned earlier, most companies are still using Python 2 for legacy reasons, but more and more companies are using Python 3, or beginning to make the switch from 2 to 3.

So, let’s look at Instagram and Facebook–two companies that have switched from Python 2 to 3 or are in the process of doing so–and why they chose to do so.