重学python基础

gwuj

http://linux.chinaitlab.com/manual/python_chinese/
学python已经是第4遍了，这次让我学精吧
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help('print')
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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 ’‘’   
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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
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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'
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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
只有在形参表末尾的那些参数可以有默认参数值，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)
可以不按照顺序，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__