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182 lines
2.7 KiB
Markdown
182 lines
2.7 KiB
Markdown
# sys 模块简介
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In [1]:
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```py
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import sys
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```
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## 命令行参数
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`sys.argv` 显示传入的参数：
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In [2]:
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```py
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%%writefile print_args.py
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import sys
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print sys.argv
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```
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```py
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Writing print_args.py
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```
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运行这个程序：
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In [3]:
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```py
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%run print_args.py 1 foo
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```
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```py
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['print_args.py', '1', 'foo']
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```
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第一个参数 （`sys.args[0]`） 表示的始终是执行的文件名，然后依次显示传入的参数。
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删除刚才生成的文件：
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In [4]:
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```py
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import os
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os.remove('print_args.py')
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```
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## 异常消息
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`sys.exc_info()` 可以显示 `Exception` 的信息，返回一个 `(type, value, traceback)` 组成的三元组，可以与 `try/catch` 块一起使用：
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In [5]:
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```py
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try:
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x = 1/0
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except Exception:
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print sys.exc_info()
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```
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```py
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(<type 'exceptions.ZeroDivisionError'>, ZeroDivisionError('integer division or modulo by zero',), <traceback object at 0x0000000003C6FA08>)
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```
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`sys.exc_clear()` 用于清除所有的异常消息。
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## 标准输入输出流
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* sys.stdin
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* sys.stdout
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* sys.stderr
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## 退出Python
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`sys.exit(arg=0)` 用于退出 Python。`0` 或者 `None` 表示正常退出，其他值表示异常。
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## Python Path
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`sys.path` 表示 Python 搜索模块的路径和查找顺序：
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In [6]:
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```py
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sys.path
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```
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Out[6]:
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```py
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['',
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'C:\\Anaconda\\python27.zip',
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'C:\\Anaconda\\DLLs',
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'C:\\Anaconda\\lib',
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'C:\\Anaconda\\lib\\plat-win',
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'C:\\Anaconda\\lib\\lib-tk',
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'C:\\Anaconda',
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'C:\\Anaconda\\lib\\site-packages',
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'C:\\Anaconda\\lib\\site-packages\\Sphinx-1.3.1-py2.7.egg',
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'C:\\Anaconda\\lib\\site-packages\\cryptography-0.9.1-py2.7-win-amd64.egg',
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'C:\\Anaconda\\lib\\site-packages\\win32',
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'C:\\Anaconda\\lib\\site-packages\\win32\\lib',
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'C:\\Anaconda\\lib\\site-packages\\Pythonwin',
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'C:\\Anaconda\\lib\\site-packages\\setuptools-17.1.1-py2.7.egg',
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'C:\\Anaconda\\lib\\site-packages\\IPython\\extensions']
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```
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在程序中可以修改，添加新的路径。
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## 操作系统信息
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`sys.platform` 显示当前操作系统信息：
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* `Windows: win32`
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* `Mac OSX: darwin`
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* `Linux: linux2`
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In [7]:
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```py
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sys.platform
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```
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Out[7]:
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```py
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'win32'
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```
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返回 `Windows` 操作系统的版本：
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In [8]:
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```py
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sys.getwindowsversion()
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```
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Out[8]:
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```py
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sys.getwindowsversion(major=6, minor=2, build=9200, platform=2, service_pack='')
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```
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标准库中有 `planform` 模块提供更详细的信息。
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## Python 版本信息
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In [9]:
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```py
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sys.version
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```
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Out[9]:
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```py
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'2.7.10 |Anaconda 2.3.0 (64-bit)| (default, May 28 2015, 16:44:52) [MSC v.1500 64 bit (AMD64)]'
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```
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In [10]:
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```py
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sys.version_info
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```
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Out[10]:
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```py
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sys.version_info(major=2, minor=7, micro=10, releaselevel='final', serial=0)
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``` |