If you do much work on computers, eventually you find that there’s some task you’d like to automate. For example, you may wish to perform a search-and-replace over a large number of text files, or rename and rearrange a bunch of photo files in a complicated way. Perhaps you’d like to write a small custom database, or a specialized GUI application, or a simple game.
如果你使用电脑进行许多工作，最终你发现这些工作，你可以自动去完成。例如：你想要在大量的文本文件里查找-替换这里面的某些东西，亦或者通过一个复杂的方法来给一些照片重新命名或者重新设置。尽管你想要写一个自定义的数据库或者一个专门的GUI（图形用户界面）应用甚至是一个简单的游戏。
If you’re a professional software developer, you may have to work with several C/C++/Java libraries but find the usual write/compile/test/re-compile cycle is too slow. Perhaps you’re writing a test suite for such a library and find writing the testing code a tedious task. Or maybe you’ve written a program that could use an extension language, and you don’t want to design and implement a whole new language for your application.
如果你是一个程序员，你可能会经常用到许多C、C++或Java的函数库，但是你会发现这是通常的写入/编译/测试/再编译的环节是非常缓慢的。尽管你正在编写一个测试程序来适应这些函数库同时你又发现编写测试代码是一项枯燥乏味的工作，亦或者你已经使用一种延展语言写出了一个程序，而且你不想要为了你的应用重新设计和实现整个新语言。
Python is just the language for you.
Python就是你想要的这种语言
You could write a Unix shell script or Windows batch files for some of these tasks, but shell scripts are best at moving around files and changing text data, not well-suited for GUI applications or games. You could write a C/C++/Java program, but it can take a lot of development time to get even a first-draft program. Python is simpler to use, available on Windows, Mac OS X, and Unix operating systems, and will help you get the job done more quickly.
你可以为了某一项工作编写一个UNIX的Shell脚本或者windows的批处理文件，但是Shell 脚本在移动文件和更改文本数据的时候有着更好的使用效果，但是在GUI应用或者游戏上却不能够完整的与之相适，你可以编写一个C、C++或Java的程序，但是这会花费很多的开发时间甚至会使用一种从未出现的程序。Python可以更简单的在Windows、Mac OS X甚至是Unix操作系统上去使用，而且这会帮助你更加快速的获得一个工作。
Python is simple to use, but it is a real programming language, offering much more structure and support for large programs than shell scripts or batch files can offer. On the other hand, Python also offers much more error checking than C, and, being a very-high-level language, it has high-level data types built in, such as flexible arrays and dictionaries. Because of its more general data types Python is applicable to a much larger problem domain than Awk or even Perl, yet many things are at least as easy in Python as in those languages.
Python尽管可以简单的去使用，但是她确实是一个真正的编程语言。相比于Shell脚本和批处理文件，Python为大型的程序提供了更多的结构和支持。在另一方面，相比于C语言，Python可以提供更多错误检测。而且，做为一种非常高级的编程语言，她有高级数据类型构建，像灵活的数组和词典。因为相比于Awk和Perl这两种语言，Python在大型问题的领域应用更多的总数据类型，因而许多事情相比于其他语言在Python处理起来更加的简单。
Python allows you to split your program into modules that can be reused in other Python programs. It comes with a large collection of standard modules that you can use as the basis of your programs — or as examples to start learning to program in Python. Some of these modules provide things like file I/O, system calls, sockets, and even interfaces to graphical user interface toolkits like Tk.Python is an interpreted language（解释型语言）, which can save you considerable time during program development because no compilation and linking is necessary. The interpreter can be used interactively, which makes it easy to experiment with features of the language, to write throw-away programs, or to test functions during bottom-up program development. It is also a handy desk calculator.
Python enables programs to be written compactly and readably. Programs written in Python are typically much shorter than equivalent C, C++, or Java programs, for several reasons:
·the high-level data types allow you to express complex operations in a single statement;
·statement grouping is done by indentation instead of beginning and ending brackets;
·no variable or argument declarations are necessary.
Python is extensible: if you know how to program in C it is easy to add a new built-in function or module to the interpreter, either to perform critical operations at maximum speed, or to link
Python programs to libraries that may only be available in binary form (such as a vendor-specific graphics library). Once you are really hooked, you can link the Python interpreter into an
application written in C and use it as an extension or command language for that application.
By the way, the language is named after the BBC show “Monty Python’s Flying Circus” and has nothing to do with reptiles. Making references to Monty Python skits in documentation is not only
allowed, it is encouraged!
Now that you are all excited about Python, you’ll want to examine it in some more detail. Since the best way to learn a language is to use it, the tutorial invites you to play with the Python
interpreter as you read.
In the next chapter, the mechanics of using the interpreter are explained. This is rather mundane information, but essential for trying out the examples shown later.
The rest of the tutorial introduces various features of the Python language and system through examples, beginning with simple expressions, statements and data types, through functions and
modules, and finally touching upon advanced concepts like exceptions and user-defined classes.