Python学习笔记2(函数)
#callback 判断是否存在 import match x = 1 y = math.sqrt callable(x) #False callable(y) #True #函数 def fib(num): result = [0,1] for i in range(num-2): result.append(result[-2],result[-1]) return result; fibs(10) #[0,1,1,2,3,5,8,13,21,34] #函数文档 def square(x): 'Calcutates the square of the number x' return x*x square.__doc__ #'Calcutates the square of the number x' #None def test(): print 'This is printed' return print 'This is not' x = test() #This is printed print x #None #改变列表 def change(n): n[0] = 'Mr.Gumby' names = ['Mr.Entiy','Mrs.Thing'] change(names) print names #['Mr,Gumby','Mrs.Thing'] #复制列表 names = ['1','2'] n = names[:] n is names #False n == names #True #位置参数 def hello_1(greeting,name): print '%s,%s!' % (greeting,name) def hello_2(name,greeting): print '%s,%s!' % (name,greeting) hello_1('Hello','World') #Hello,World hello_2('Hello','World') #Hello,World hello_2(greeting='Hello',name='World') #World,Hello #收集参数 def print_params(title,*params): print title print params print_params('params:',1,2,3) #params: #(1,2,3) def print_params2(title,**params): print title print params print_params2('params:',x=1,y=2,z=3) #{'z':3,'x':1,'y':2}