语法错误无效语法。不知道为什么

Question

height = float(input("enter your height in m: "))
weight = float(input("enter your weight in kg: "))
bmi = weight / height ** 2
bmi2 = int(bmi)
if bmi2 < 18.5:
    print(f"Your BMI is {bmi2}, you are underweight")
    elif bmi2 > 18.5 < 25:
        print(f"Your BMI is {bmi2}, you are normal weight")
    elif bmi2 > 25 < 30:
        print(f"Your BMI is {bmi2}, you are slightly overweight")
    elif bmi2 > 30 < 35:
        print(f"Your BMI is {bmi2}, you are obese")
else:
    print(f"Your BMI is {bmi2}, you are cliniclly obese")

它说“elif bmi2 > 18.5 < 25：”这部分的语法错误无效语法，但我不知道为什么

Answer 1

问题是缩进。稍后我还有其他一些事情。

这就是您的脚本以使其工作的方式：

#!/usr/bin/env python3

height = float(input("enter your height in m: "))
weight = float(input("enter your weight in kg: "))
bmi = weight / height**2
bmi2 = int(bmi)

if bmi2 < 18.5:
    print(f"Your BMI is",bmi2," you are underweight")
elif  18.5 < bmi2 <= 24.99:
    print(f"Your BMI is",bmi2," you are normal weight")
elif 24.99 < bmi2 <= 29.99:
    print(f"Your BMI is ",bmi2," you are slightly overweight")
elif 30 <= bmi2 <= 34.99:
    print(f"Your BMI is ",bmi2," you are obese")
else:
    print(f"Your BMI is ",bmi2," you are clinically obese")

如果和else条件应与行的开头一致。只有在有嵌套的陈述（例如

if apple > 5;
    if orange > 3;

，依此类推，依此类推）时，才会缩进内部。您的脚本没有该脚本，因此不需要在语句上有任何缩进。

以这种格式大于或低于或小的语法：

elif  value < variable < value2:

将条件设置为大于价值的条件，但小于值二。实际上，使用它的方式，它实际上是在第一个情况下设置条件，因为BMI大于18.5和18.5小于25。这将导致每个bmi2超过18.5会导致正常体重，因为无论BMI2在这种情况下，第二个条件的第二种条件少于25，无论人们进入什么都会始终是正确的。

为了准确性，我还将第二个语句中的少于25更改为小于或等于24.99，大于25 更大大于24.99和小于30 to 小于或等于第三个语句中的29.99，最后，大于30 大于或等于30和小于35 to 小于或等于第三个语句中的34.99，因为这与范围从实际的BMI计算器和prvents来自重叠值的其他偶然性。

既然重要的东西已经涵盖了，我还进行了一些化妆品的更改，包括在变量声明之间添加空白，并使用逗号和报价将变量bmi2与文本分开。这使得判断哪一个是谁和正在发生的事情变得容易一些。

Answer 2

height = float(input("enter your height in m: "))
weight = float(input("enter your weight in kg: "))

height_2 = height*height
BMI = weight/height_2
BMI2=round(BMI)
if BMI2 <=18.5:
    print(f"Your BMI is {BMI2}, you are underweight.")
elif 18.6< BMI2 <= 24.99:
    print(f"Your BMI is {BMI2}, you have a normal weight.")
elif 25< BMI2 <=29.99:
    print(f"Your BMI is {BMI2}, you are slightly overweight.")
elif 30 < BMI2 <= 34.99:
    print(f"Your BMI is {BMI2}, you are obese.")
elif BMI2 > 35:
    print(f"Your BMI is {BMI2}, you are clinically obese.")
else:
    print(f"Your BMI is {BMI2}, you are clinically obese.")