1、Python基础

简明python教程：http://woodpecker.org.cn/abyteofpython_cn/chinese/

进入python：

1. [[email protected] ~]# python 
2. Python2.6.5(r265:79063,Jul142010,11:36:05) 
3. [GCC 4.4.420100630(RedHat4.4.4-10)] on linux2
4. Type"help","copyright","credits" or "license"for more information.
5. >>> 

退出python

[ CTRL + d ]

查看版本：

[[email protected] ~]# python -V

Python 2.6.5

执行第一个hello程序

1. [[email protected] ~]# cat hello.py 
2. #!/usr/bin/python
3. print‘hello!‘
4. [[email protected] ~]# 
5. [[email protected] ~]# python hello.py 
6. hello!

print加颜色：

>>> print ‘\033[31;1mHello world!\033[0m‘

print重复输出字符：

>>> print (‘a‘*5)

aaaaa

读取用户输入：

>>> A = raw_input(‘pleas input:‘)

pleas input:hello!

>>> print A

hello!

保证输入为数字：

>>> A = int(raw_input(‘pleas input number:‘))

pleas input number:sdf

Traceback (most recent call last):

File "<stdin>", line 1, in <module>

ValueError: invalid literal for int() with base 10: ‘sdf‘

转换数字为字符：

>>> str(12)

‘12‘

简单计算：

>>> 2 * 3

6

>>> 32/4

8

>>> b=2+3

>>> print b

5

变量：

1. >>> name=‘Likun‘        --定义，并给变量赋值，字符类型要加引号
2. >>> print name
3. Likun
4. >>> name1=name        --变量之间传递赋值
5. >>> print name1
6. Likun
7. >>> print ‘%s is good‘%name1       --%s 为变量占位符
8. Likun is good
9. >>> name1=addr            --addr未加引号，会当做变量而不是字符，找不到变量因此报错
10. Traceback(most recent call last):
11.   File"<stdin>", line 1, in <module>
12. NameError: name ‘addr‘ is not defined

变量使用单引、双引、三引的区别

正常字符串用单引

本身带单引的字符串用双引

三引可以引住多行字符

1. [[email protected] python_scripts]# cat 1hello.py
   #!/usr/bin/python
   print ‘hello!‘
   print "what‘s your name?"
   n=‘‘‘good morning
   everyone,
   come on !‘‘‘
   print n

‘‘‘    ‘‘‘ 可以用来注释多行代码

小练习：兑换人民币

1. [[email protected] python_scripts]# cat 3rate.py
   #!/usr/bin/python
   print ‘The rate between HK$ and US$ to RMB\n‘
   rmb =int(raw_input(‘input how much RMB you want to change:‘))    --int后才能做浮点运算
   HK=rmb /0.84
   US=rmb /6.4
   print ‘HK=‘,HK,‘,US=‘,US                --拼接用逗号

1. [[email protected] python_scripts]# python 3rate.py 
2. The rate between HK$ and US$ to RMB
4. input how much RMB you want to change:10
5. HK=11.9047619048,US=1.5625

缩进要求：

逻辑上同一层级的，要对齐，不对齐会报错

不同层级的必须有缩进，否则也会报错

缩进可以选择制表符、单空格、双空格，全文一定要保证缩进上下一致

1. [[email protected] python_scripts]# cat 1hello.py
   #!/usr/bin/python
   print ‘hello!‘
   print ‘world‘
   for i in range(1,5):
           print i    

python命令自动补全脚本：

vim ~/.pythonstartup

import sys
import readline
import rlcompleter
import atexit
import os
readline.parse_and_bind(‘tab: complete‘)
histfile = os.path.join(os.environ[‘HOME‘], ‘.pythonhistory‘)
try:
    readline.read_history_file(histfile)
except IOError:
    pass
atexit.register(readline.write_history_file, histfile)
del os, histfile, readline, rlcompleter

echo "export PYTHONSTARTUP=~/.pythonstartup" >> ~/.bashrc