1.传递多个参数
使用*号,表示函数接受多个参数
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>>> def f(*args):
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print args
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>>> f(1)
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(1,)
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>>> f(1,2,3)
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(1, 2, 3)
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>>> f()
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()
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>>> f(1,2)
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(1, 2)
>>> 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
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>>> def f1(**args):
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print args
-
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>>> f1(a=1,b=2)
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{'a': 1, 'b': 2}
>>> 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
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-
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def minmax(test,*args):
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res=args[0]
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for arg in args[1:]:
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if test(arg,res):
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res=arg
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return res
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def lessthan(x,y):return x<y
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def grtrthan(x,y):return x>y
-
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print minmax(lessthan,4,7,9,22,2,18)
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print minmax(grtrthan,4,7,9,22,2,18)
#coding=utf-8 #用来支持中文,=号前后不能有空格
#minmax.py
def 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 res
def lessthan(x,y):return x<y
def grtrthan(x,y):return x>y
print minmax(lessthan,4,7,9,22,2,18)
print minmax(grtrthan,4,7,9,22,2,18)
4.传递混合参数
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>>> def f2(a,*pargs,**kargs):
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print a,pargs,kargs
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>>> f2(1,2,3,4,5,x=11,y=12)
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1 (2, 3, 4, 5) {'y': 12, 'x': 11}
>>> 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
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>>> def intersct(*args):
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res=[]
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for x in args[0]:
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for other in args[1:]:
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if x not in other:break
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else:res.append(x)
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return res
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>>> def union(*args):
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res=[]
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for seq in args:
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for x in seq:
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if not x in res:
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res.append(x)
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return res
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>>> s1,s2,s3="SPAM","SCAM","SLAM"
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>>> intersct(s1,s2)
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['S', 'A', 'M']
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>>> union(s1,s2)
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['S', 'P', 'A', 'M', 'C']
>>> def intersct(*args):
res=[]
for x in args[0]:
for other in args[1:]:
if x not in other:break
else: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
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>>> class C:
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X = 33
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def m(self):
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X = 44
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self.X = 55
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>>> obj = C()
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>>> print obj.X
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33
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>>> obj.m()
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>>> print obj.X
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55
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>>> C.X
-
33
>>> class C:
X = 33
def m(self):
X = 44
self.X = 55
>>> obj = C()
>>> print obj.X
33
>>> obj.m()
>>> print obj.X
55
>>> C.X
33
6.练习--打印类的继承关系树
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<span style="font-size: 12px;">>>> def classtree(cls,indent):
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print '.'*indent,cls.__name__
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for supercls in cls.__bases__:
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classtree(supercls,indent+3)
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-
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>>> def instancetree(inst):
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print 'Tree of ',inst
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classtree(inst.__class__,3)
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-
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>>> def selftest():
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class A:pass
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class B(A):pass
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class C(A):pass
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class D(B,C):pass
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class E:pass
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class F(D,E):pass
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instancetree(B())
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instancetree(F())
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-
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>>> selftest()
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Tree of <__main__.B instance at 0x012E1A08>
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... B
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...... A
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Tree of <__main__.F instance at 0x012E1A08>
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... F
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...... D
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......... B
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............ A
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......... C
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............ A
-
...... E
>>> def classtree(cls,indent):
print '.'*indent,cls.__name__
for supercls in cls.__bases__:
classtree(supercls,indent+3)
>>> def instancetree(inst):
print 'Tree of ',inst
classtree(inst.__class__,3)
>>> def selftest():
class A:pass
class B(A):pass
class C(A):pass
class D(B,C):pass
class E:pass
class F(D,E):pass
instancetree(B())
instancetree(F())
>>> selftest()
Tree of <__main__.B instance at 0x012E1A08>
... B
...... A
Tree of <__main__.F instance at 0x012E1A08>
... F
...... D
......... B
............ A
......... C
............ A
...... E
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