[FIXED] How can I get Python to recognize comma as the decimal point in user input?

Issue

Super beginner here.

I'm following along the Automate the Boring Stuff With Python book and I decided to make a little script to help me out with some basic percentage checking. I didn't want to open Excel everytime I wanted to do this.

So the script gets two inputs, an old price and a new price and then calculates the percentage change in price. I think I got that right.

The problem occurs once I try to enter a float (that's the right term, yeah?) and I use the comma here in Europe.

I found a topic here where a similar question was answered, but there seems to be an issue on whether or not to call setlocale and (as far as I understand it) it does not deal with how to convert an input?

My code is below:

    def izracun_odstotkov():    #function to calculate the difference in % between original price and new price
    while True:
        try:
            prvotna_cena = float(input('Prosim vnesi prvotno ceno:')) #original price
        except ValueError:
            print('Oprosti, to ni veljavni podatek. Vnesi stevilko.')
            continue

        if prvotna_cena == 0:
                print('Prvotna cena ne more biti 0.')
        else:
            break

    while True:
        try:
            nova_cena = float(input('Prosim vnesi novo ceno:')) #new price
        except ValueError:
            print('Oprosti, to ni veljavni podatek. Vnesi stevilko.')
            continue
        else:
            break

    print(round((float (nova_cena)- float (prvotna_cena))/ float (prvotna_cena)*100, 2), '%')

while True:
    izracun_odstotkov() #This makes the script run over and over so the user can just keep checking the % changes.

Solution

You can use the replace method:

prvotna_cena = float(input('Prosim vnesi prvotno ceno:').replace(',','.'))

Answered By - Ann Zen

Answer Checked By - Pedro (PHPFixing Volunteer)