算術運算子

1. 假設 a=15 b=10

   [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=15
   >>> b=10
   >>> a+b
   25
   >>> a-b
   5
   >>> a*b
   150
   >>> a/b
   1.5
   >>> a%b
   5
   >>> a**5
   759375
   >>> a//b      ##除法只留整數 
   1
   >>> 32.8/9
   3.644444444444444
   >>> 32//9
   3
   >>> -32//9    ##結果是負的時，取地板值， -3.64... ==> -4
   -4
   >>> -32.8//9
   -4.0
   >>> quit()
   

2. 算術運算子優先序

   1. **
   2. * / % //
   3. + -