Python函数参数传递以及变量作用域

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1.传递多个参数

使用*号，表示函数接受多个参数

>>> def f(*args):print args>>> f(1)(1,)>>> f(1,2,3)(1, 2, 3)>>> f()()>>> f(1,2)(1, 2)

2.传递字典参数

使用**号，表示传递的是字典参数

>>> def f1(**args):print args>>> f1(a=1,b=2){'a': 1, 'b': 2}

3.将函数名作为参数传递

#coding=utf-8               #用来支持中文，=号前后不能有空格#minmax.pydef minmax(test,*args):    res=args[0]    for arg in args[1:]:    #循环args中内容副本        if test(arg,res):            res=arg    return resdef lessthan(x,y):return x<ydef grtrthan(x,y):return x>yprint minmax(lessthan,4,7,9,22,2,18)print minmax(grtrthan,4,7,9,22,2,18)

4.传递混合参数

>>> def f2(a,*pargs,**kargs):print a,pargs,kargs>>> f2(1,2,3,4,5,x=11,y=12)1 (2, 3, 4, 5) {'y': 12, 'x': 11}

5.练习--字符串∪和∩运算

>>> def intersct(*args):res=[]for x in args[0]:for other in args[1:]:if x not in other:breakelse:res.append(x)return res>>> def union(*args):res=[]for seq in args:for x in seq:if not x in res:res.append(x)return res>>> s1,s2,s3="SPAM","SCAM","SLAM">>> intersct(s1,s2)['S', 'A', 'M']>>> union(s1,s2)['S', 'P', 'A', 'M', 'C']

6.类成员变量和实例变量

>>> class C:    X = 33    def m(self):    X = 44    self.X = 55>>> obj = C()>>> print obj.X33>>> obj.m()>>> print obj.X55>>> C.X33

6.练习--打印类的继承关系树

>>> def classtree(cls,indent):print '.'*indent,cls.__name__for supercls in cls.__bases__:classtree(supercls,indent+3)>>> def instancetree(inst):print 'Tree of ',instclasstree(inst.__class__,3)>>> def selftest():class A:passclass B(A):passclass C(A):passclass D(B,C):passclass E:passclass F(D,E):passinstancetree(B())instancetree(F())>>> selftest()Tree of  <__main__.B instance at 0x012E1A08>... B...... ATree of  <__main__.F instance at 0x012E1A08>... F...... D......... B............ A......... C............ A...... E