Exercise29、30、31(logic list, if-statement(if/elif/else), python的缩进 )

ex27

logic list:

        and
        or
        not 
        !=
        ==
        >=
        <=
        True

        False

True or True == True

True or False = False

False or False = False

True and True = True

True and False = False

False and False = False

not True = False

not False = True

ex29.py

if-statement

ex30.py

注意，if,elif,else就行了。

ex31.py

python的缩进问题，注意冒号下必须要缩进一个 tab，注意空格加tab会报错。