回傳值

1. 範例：沒有 retrun 時，python 自動回傳 None。

   [dywang@deyu zzz]$ cat function4.py 
   #!/usr/bin/python3
   # coding: utf-8
   
   def add( x1, x2 ):
   	result = x1 + x2
   	return
   
   return_value = add(1,2)
   print("return_type = ", type(return_value))
   print("return_value = ", return_value)
   

2. 執行結果：回傳值是 None，type 是 NoneType。

   [dywang@deyu zzz]$ ./function4.py 
   return_type =  <class 'NoneType'>
   return_value =  None
   

3. 範例：arithmetic 函式回傳加減乘除四則運算四個值。

   [dywang@deyu zzz]$ cat function5.py 
   #!/usr/bin/python3
   # coding: utf-8
   
   def arithmetic( x1, x2 ):
   	add = x1 + x2
   	sub = x1 - x2
   	mul = x1 * x2
   	div = x1 / x2
   	return add, sub, mul, div
   
   a,s,m,d = arithmetic(20,10)
   print("x1 + x2 = %d" % a)
   print("x1 - x2 = %d" % s)
   print("x1 * x2 = %d" % m)
   print("x1 / x2 = %d" % d)
   

4. 執行結果：印出 arithmetic 函式回傳加減乘除四則運算四個值。

   [dywang@deyu zzz]$ ./function5.py 
   x1 + x2 = 30
   x1 - x2 = 10
   x1 * x2 = 200
   x1 / x2 = 2