python 分支语句 等值判断 逻辑运算符

# 分支语句
age = 233
if age < 18:
    print('您还未满18岁,禁止入内')
elif age > 18 and age < 60:
    print("欢迎光临,年龄在18-60之间")
else:
    print("欢迎光临，年龄大于60岁")

weight = input('体重(kg): ')
height = input("身高(cm):")
#体重/ 身高的平方  pow(4,2) = 16
bmi =  int(weight) / pow(float(height), 2)
print(bmi)

if  bmi <= 18.4:
    print('偏瘦')
elif bmi > 18.4 and bmi <=23.9:
    print('正常')
elif bmi > 23.9 and bmi <= 27.9:
    print('过重')
else:
    print('肥胖')



# 等值判断
print(1 == 1.0)  #true
print(1 == '1')  #false
print(1 == int('1'))  #true

# 逻辑运算符 优先级 not > and > or
a = 4 > 1   #true
b = 5 < 2   #false
c = 8 == 8  #true
d = 9 < 6   #false

print( a and b)  #false
print( a and c)  #true
print( a or b)   #true
print( d or b)    #false
print(not a)    #false
print(not b)    #true

r1 = a and b or c and not d
#  a and b or c and  true
#  false or  true
#  true
print(r1) # true

r2 = (a and (not b or c)) and d
# (a and (true or c)) and d
# (a and true) and d
# true and  false
# false
print(r2) # false