邏輯運算子

1. 邏輯(logical)運算子，主要用在組合判斷狀況。

   [dywang@kvm8 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.
   >>> x=7
   >>> x<10 and x>5
   True
   >>> x<5 or x>10
   False
   >>> not(x<5 or x>10)
   True
   >>> quit()