指派運算子

1. 運算結果指派回原變數

   [dywang@deyu 10827000]$ python3
   Python 3.6.8 (default, Mar 19 2021, 05:13:41)
   [GCC 8.4.1 20200928 (Red Hat 8.4.1-1)] on linux
   Type "help", "copyright", "credits" or "license" for more information.
   >>> a=10; a+=5; print(a)
   15
   >>> a=10; a-=5; print(a)
   5
   >>> a=10; a/=5; print(a)
   2.0
   >>> a=10; a%=5; print(a)
   0
   >>> a=10; a//=5; print(a)
   2
   >>> a=10; a**=5; print(a)
   100000
   

2. 多重指定

   >>> a=b=c=10
   >>> print(a,b,c)
   10 10 10
   >>> a,b,c=10,20,30
   >>> print(a,b,c)
   10 20 30
   

3. 變數交換

   >>> a,b=10,20
   >>> print(a,b)
   10 20
   >>> a,b=b,a
   >>> print(a,b)
   20 10
   

4. 刪除變數

   >>> del a
   >>> print(a)
   Traceback (most recent call last):
     File "<stdin>", line 1, in <module>
   NameError: name 'a' is not defined
   >>> quit()