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