重学python基础

http://linux.chinaitlab.com/manual/python_chinese/
学python已经是第4遍了，这次让我学精吧
-------
help('print')
---------
单引和双引是相同的
u‘string’ U'string' unicode
r'\nstring' R'\nstring' 不转意
‘string \
string'
‘’‘string
string ’‘’
---------
运算符http://linux.chinaitlab.com/manual/python_chinese/ch05s02.html
/ 除
// 取整除
% 取余数
运算符优先级http://linux.chinaitlab.com/manual/python_chinese/ch05s03.html
-----------
在Python中没有switch语句
if guess == number:
elif guess < number:
else:
或字典
-----------
while running:
else:
---------------
for i in range(1, 5):
print i
else:
print 'The for loop is over'
---------------
靠，啥玩意都能用else
--------

#!/usr/bin/python
# Filename: break.py

while True:
    s = raw_input('Enter something : ')
    if s == 'quit':
        break
    print 'Length of the string is', len(s)
print 'Done' 

break也能在for中使用

#!/usr/bin/python
# Filename: continue.py

while True:
    s = raw_input('Enter something : ')
    if s == 'quit':
        break
    if len(s) < 3:
        continue
    print 'Input is of sufficient length'
    # Do other kinds of processing here... 

---------------global-------

#!/usr/bin/python
# Filename: func_global.py

def func():
    global x

    print 'x is', x
    x = 2
    print 'Changed local x to', x

x = 50
func()
print 'Value of x is', x 

----默认参数-----

#!/usr/bin/python
# Filename: func_default.py

def say(message, times = 1):
    print message * times

say('Hello')
say('World', 5) 

重要
[color=red]只有在形参表末尾的那些参数可以有默认参数值[/color]，即你不能在声明函数形参的时候，先声明有默认值的形参而后声明没有默认值的形参。
--------------关键参数------

#!/usr/bin/python
# Filename: func_key.py

def func(a, b=5, c=10):
    print 'a is', a, 'and b is', b, 'and c is', c

func(3, 7)
func(25, c=24)
func(c=50, a=100) 

[color=red]可以不按照顺序[/color]，有默认值的可以不赋值
------pass---------
def someFunction():
pass
---------__doc__-----------

#!/usr/bin/python
# Filename: func_doc.py

def printMax(x, y):
    '''Prints the maximum of two numbers.

    The two values must be integers.'''
    x = int(x) # convert to integers, if possible
    y = int(y)

    if x > y:
        print x, 'is maximum'
    else:
        print y, 'is maximum'

printMax(3, 5)
print printMax.__doc__ 

[code="java"][/code]