python函数入门

x=print（'a'）#返回a

print（a）  #返回None

下面介绍三种分数的程序员

a=[1,2,3,4]  #想让输出结果显示次数和数字一样（按总分五分来比较）

显示结果为：  

1

22

333

4444

第一种方法：  （三分）                               第二种方法： （四分）                                    

for x in a：                                               for  x in a:                                                 

    if x==1：                                                  if x==1:                                                          

       print（x）                                                 print('1')

    elif x==2：                                                if x==2:                                      

       print（str（x）*2）                                     print('22')                                                                                      

    else：#else后面不能跟条件                            if x==3:                                                                                        

       if x==3：                                                   print('333')                                                                                        

          print（str（x）*3）                               if x=4:                                           

       else：                                                         print('4444')

          print(str（x）*4)

 

第三种方法：（五分）

for x in  a：

     print（str（x）*x）

 

当需求变更为（a=[1,2,3,4,5,6,7,8]），第一种必须改改能实现基本功能， 显然比较麻烦

第二种也需要增加，简捷方便一点

第三种则不需要改变，最简洁省事

 

下面我将用函数来写一下：

第一种函数写法：                                                                                        第二种函数写法  ：                  

def jiang（shuzu）：                                                                                                             def jiang（a=[1，2，3，4]）：                

    for  x  in  shuzu：#shuzu是变量名 、局部变量、 型式参数                                                                for x in a：

         print（str（x）*x）                                                                                                                   print(str（x）*x)

jiang(a)                                                                                                                                jiang()