实例5：身体质量指数BMI

BMI：对身体质量的刻画

BMI：Body Mass Index

国际上常用的衡量人体肥胖和健康程度的重要标准，主要用于统计分析

定义：

BMI = 体重 (kg) / 身高2 (m2)

程序代码1：

#CalBMIv1.py

height, weight = eval(input("请输入身高(米)和体重\(公斤)[逗号隔开]: "))

bmi = weight / pow(height, 2) 

print("BMI 数值为：{:.2f}".format(bmi)) 

who = ""

if bmi < 18.5:

who = "偏瘦"

elif 18.5 <= bmi < 25:  who = "正常"

elif 25 <= bmi < 30:  who = "偏胖"

else:

who = "肥胖"

print("BMI 指标为:国际'{0}'".format(who))

两种不同标准的BMI

程序代码2：

#CalBMIv3.py

height, weight = eval(input("请输入身高(米)和体重\(公斤)[逗号隔开]: "))

bmi = weight / pow(height, 2) 

print("BMI 数值为：{:.2f}".format(bmi)) 

who, nat = "", ""

if bmi < 18.5:

who, nat = "偏瘦", "偏瘦"

elif 18.5 <= bmi < 24: 

who, nat = "正常", "正常"

elif 24 <= bmi < 25:

who, nat = "正常", "偏胖"

elif 25 <= bmi < 28:

who, nat = "偏胖", "偏胖"

elif 28 <= bmi < 30:

who, nat = "偏胖", "肥胖"

else:

who, nat = "肥胖", "肥胖"

print("BMI 指标为:国际'{0}', 国内'{1}'".format(who, nat))

代码分析（略）