Creditcard_Validator.py

#Luhn algorithm
#Credit_Card=input("Enter your credit card number: ")
Credit_Card="38520000023237"
rCredit_Card=Credit_Card[::-1]#reversing the string
sCredit_Card=rCredit_Card.strip()#removing spaces before and after a string, if any
#print(cn)
total=0
for index, value in enumerate (sCredit_Card):
    if index%2!=0: #extracting even position of digits from left to right.
        x=int(value)*2 #doubling the even position of digits from left to right
        if x>9: # addition of digits, if the valus is more than 9
            x=x-9
        total=total+x
        #print(total)
    else:
        x=int(value) #extracting odd position of digits from left to right.
        total=total+x
total=total

#print(total)
if total%10==0:
    
    
    if ((len(Credit_Card)==15) and (Credit_Card[:2]=="34" or Credit_Card[:2]=="37")):
        print("Your American Express card is valid")
    elif ((len(Credit_Card)==16) and ((Credit_Card[:2]=="51") or (Credit_Card[:2]== "52") or (Credit_Card[:2]== "53") or (Credit_Card[:2]=="54") or (Credit_Card[:2]=="55"))):
        print("Your Master card is valid") 
    elif ((len(Credit_Card)==16) and (Credit_Card[0:1]=="4")):
        print("Your Visa card is valid")
    else:
        print("Your Card is valid, but check your card provider")
else:
    print("This is not a valid card")