python - TypeError: unsupported operand type(s) for &: 'float' and 'float'

Question

I wrote this simple program to calculate one's BMI. But I am unable to execute it complete. Below is my program,

PROGRAM

h = input("Please Enter your height in meters:")
q = raw_input("Do you want to enter your weight in kg or lbs?")

if q=="kg":
         w1 = input("Please Enter your weight in kgs:")
         bmi1 = w1/(h*h) 
         print "Your BMI is", bmi1

         if bmi1 <= 18.5: 
                        print "Your are underweight."
         if bmi1 > 18.5 & bmi1 < 24.9: 
                                     print "Your weight is normal."
         if bmi1 > 25 & bmi1 < 29.9: 
                                   print "Your are overweight"              
         if bmi1 >= 30: 
                      print "Your are obese"                    


if q=="lbs":
          w2 = input("Please Enter your weightin lbs:")
          bmi2 = w2/((h*h)*(39.37*39.37)*703) 
          print "Your BMI is:", bmi2

          if bmi2<= 18.5: 
                        print "Your are underweight."
          if bmi2>18.5 & bmi2<24.9: 
                                  print "Your weight is normal."
          if bmi2>25 & bmi2<29.9: 
                                print "Your are overweight"         
          if bmi2>=30: 
                     print "Your are obese" 

OUTPUT

Please Enter your height in meters:1.52
Do you want to enter your weight in kg or lbs?kg
Please Enter your weight in kgs:51
Your BMI is 22.074099723
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "bmi.py", line 11, in <module>
    if bmi1 > 18.5 & bmi1 < 24.9: 
TypeError: unsupported operand type(s) for &: 'float' and 'float'

Where am I going wrong? Anyone just let me know..

Thanks :).

Answer 1

& is a bitwise operator, I think you were looking for the boolean and.

But notice that Python also supports the following syntax:

if 18.5 < bmi1 < 24.9:
    # ...

---

Since you seemed to have trobled with indentation this is how your script might look like:

h = raw_input("Please enter your height in meters: ")
h = float(h)
w_unit = raw_input("Do you want to enter your weight in kg or lbs? ")
w = raw_input("Please enter your weight in {}: ".format(w_unit))
w = int(w)
if w_unit == "kg":
    bmi = w / (h*h)
elif w_unit == "lbs":
    bmi = w / ((h*h) * (39.37 * 39.37) * 703)

print "Your BMI is {:.2f}".format(bmi)
if bmi <= 18.5: 
    print "Your are underweight."
elif 18.5 < bmi <= 25: 
    print "Your weight is normal."
elif 25 < bmi < 30: 
    print "Your are overweight"              
elif bmi >= 30:
    print "Your are obese"

There are a couple of slight improvements:

• The explicit conversion (since in Python 3 the input function behave like raw_input and there's nothing like the Python 2 input, it might be a good habit to write your input like that)
• What really changes is the bmi value, so there's no need to write two times the same thing.

Something left to do, might be wrap the whole script into functions :)