运算符

运算符

and: 并且, 两端同时为真. 结果才能是真
or: 或者, 有一个是真. 结果就是真
not: 非真既假, 非假既真

顺序: () => not => and => or

x or y:
如果x是零, 输出y
如果x是非零, 输出x

True: 非零
False: 零

print(3>4 or 4<3  and  1==1) # False
print(1 < 2  and  3 < 4 or 1>2 ) # True
print(2 > 1  and  3 < 4 or 4 > 5 and  2 < 1) # True
print(1 > 2  and  3 < 4 or 4 > 5 and  2 > 1  or 9 < 8) # False
print(1 > 1  and  3 < 4 or 4 > 5 and  2 > 1  and  9 > 8 or 7 < 6) # False
print(not  2 > 1  and 3 < 4  or 4 > 5  and 2 > 1  and 9 > 8  or 7 < 6) # False

# x or y 如果x是0 返回y, 如果x是非零, 返回x
print(1 or 2) # 1
print(1 or 0) # 1
print(0 or 1) # 1
print(0 or 2) # 2
print(0 or 1 or 2 or 3)
print(3 or 0 or 1 or 0 or 2)

# and和or相反. 不要去总结and.  记住or
print(1 and 2) # 2
print(0 and 2) # 0
print(1 and 0) # 0
print(0 and 1) # 0

print(1 and 2 or 3)
print(1 or 2 and 3)

# False: 0, True: 1(非零)
print(1 and 2>3)
print(2>3 and 1)

print(1 > 2 or 0 and 3 < 6 or 5) # 先算and 后算or