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1、Python基础

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

进入python:

  1. [root@likun ~]# 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:
[root@likun ~]# python -V
Python 2.6.5
 
执行第一个hello程序
  1. [root@likun ~]# cat hello.py 
  2. #!/usr/bin/python
  3. print‘hello!‘
  4. [root@likun ~]# 
  5. [root@likun ~]# 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. [root@likun python_scripts]# cat 1hello.py #!/usr/bin/pythonprint hello!print "what‘s your name?"n=‘‘‘good morningeveryone,come on !‘‘‘print n
‘‘‘    ‘‘‘ 可以用来注释多行代码
 
小练习:兑换人民币
  1. [root@likun python_scripts]# cat 3rate.py #!/usr/bin/pythonprint The rate between HK$ and US$ to RMB\nrmb =int(raw_input(input how much RMB you want to change:))    --int后才能做浮点运算HK=rmb /0.84US=rmb /6.4print HK=,HK,,US=,US                --拼接用逗号

     

  1. [root@likun python_scripts]# python 3rate.py 
  2. The rate between HK$ and US$ to RMB
  3. input how much RMB you want to change:10
  4. 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. [root@likun python_scripts]# cat 1hello.py #!/usr/bin/pythonprint hello!print world        for i in range(1,5):        print i    

     

python命令自动补全脚本:
vim ~/.pythonstartup 
import sysimport readlineimport rlcompleterimport atexitimport osreadline.parse_and_bind(tab: complete)histfile = os.path.join(os.environ[HOME], .pythonhistory)try:    readline.read_history_file(histfile)except IOError:    passatexit.register(readline.write_history_file, histfile)del os, histfile, readline, rlcompleter
echo "export PYTHONSTARTUP=~/.pythonstartup" >> ~/.bashrc 

 



1、Python基础