pythoninputraw-input

Inputs and user input validation

I have researched this question on here I have found similar question but this is different. I need to validate user input in the piece of code I am working on needs to print an error if the user input is either under 0 (This I have working fine) and print an error if the input is non-numeric here is where my problems are. If i use input rather than raw_input i get an error:

NameError name 'Whatever I type in' is not defined

What I tried so far:

Casting the variable as an integer and tried using the isNaN function but that failed miserably and finally going around the problem using ifs and elses. this is the code that works so far.

def pints_to_litres():
    pints = 0
    pints = input("Please enter the amount of Imperial Pints you would like converted into Litres >>>")
    litres = pints * float(0.568261)
    litres = "%.2f" % litres
    print (""+str(pints)+ " Pint(s) is equal to " +str(litres)+ " Litre(s)")
    if (pints < 0):
        print("Invalid Input! Try Again")
        pints_to_litres()

Thank you guys in advance

Solution

  • here I improved your code:

    def pints_to_litres():
    over = False
    while not over:
        try:
            pints = int(raw_input("Please enter the amount of Imperial Pints you would like converted into Litres >>>"))
            litres = pints * float(0.568261)
            print (""+str(pints)+ " Pint(s) is equal to " +str(litres)+ " Litre(s)")
            if (pints < 0):
                print("Invalid Input! Try Again")
            else:
                over = True
        except ValueError:
            print("Invalid Input! Try Again")