几个Python小程序

1：

def buildConnectionString(param):

"""

"""

return ";".join("%s=%s" %(k,v) for k,v in param.items())

if __name__=="__main__":

myParams={"server":"mpilgrim", \

"database":"master", \

"uid":"sa", \

"pwd":"secret" \

}

print buildConnectionString(myParams)

--------------------------

没什么好说的

2：

def info(object,spacing=10,collapse=1):

"""

list the api of the object

"""

methodList=[method for method in dir(object) if callable(getattr(object,method))]

processFunc=collapse and (lambda s:" ".join(s.split())) or (lambda s:s)

print "\n".join("%s %s" %(method.ljust(spacing),processFunc(str(getattr(object,method).__doc__))) for method in methodList )

if __name__=="__main__":

print info.__doc__

li=[]

info(li)

-----------------------------------------------------

methodList=[method for method in dir(object) if callable(getattr(object,method))]

注意句法， XX for in XXX if ***

processFunc=collapse and (lambda s:" ".join(s.split())) or (lambda s:s)

lambda表达式 and or

and例子

>>> 'a' and 'b'


'b'

>>> '' and 'b'


''

>>> 'a' and 'b' and 'c'


'c'

如果有假值，则返回第一个假值，否则返回最后一个真值

or例子：

>>> 'a' or 'b'


'a'

>>> '' or 'b'


'b'

>>> '' or [] or {}


{}

如果有真值，返回第一个真值，否则返回最后一个假值

lambda例子：

>>> def f(x):

... return x*2

...

>>> f(3)

6

>>> g = lambda x: x*2


>>> g(3)

6

>>> (lambda x: x*2)(3)


6