limite python entrée à int

Question

Comment puis-je faire limiter le code de l'entrée de l'utilisateur à des entiers. Le code fonctionne maintenant parfaitement mais je le veux au lieu de me donner une erreur quand il entre une chaîne, il fera juste une exception.

def miles_to_km(): 
     miles=eval(input('Amount of miles: ')) 
     result= float(miles*1.609344) 
     print(miles, 'Miles are equivalent to ', result, 'Kilometers') 
     print('----------------------------------------------------------------') 
def km_to_miles(): 
     km=eval(input('Amount of kilometers: ')) 
     result= float(km*0.62137119) 
     print(km, 'Kilometers are equivalent to ', result, 'Miles') 
     print('----------------------------------------------------------------') 
def pounds_to_kg(): 
     pounds=eval(input('Amount of pounds: ')) 
     result=float(pounds/2.2046226218) 
     print(pounds, 'Pounds are equivalent to ', result, 'Kilograms') 
     print('----------------------------------------------------------------') 
def kg_to_pounds(): 
     kg=eval(input('Amount of kilograms: ')) 
     result=float(kg*2.2046226218) 
     print(kg, 'Kilograms are equivalent to ', result, 'Pounds') 
     print('----------------------------------------------------------------') 
def C_to_F(): 
    temp=eval(input('Temperature in Celsius: ')) 
    result= float((temp*1.8)+32) 
    print(temp, '°C are equivalent to ', result, '°F') 
    print('----------------------------------------------------------------') 
def F_to_C(): 
    temp=eval(input('Temperature in Fahrenheit ')) 
    result= float((temp-32)/1.8) 
    print(temp, '°F are equivalent to ', result, '°C') 
    print('----------------------------------------------------------------') 
def mph_to_kph(): 
     mph=eval(input('Amount of Miles per hour: ')) 
     result= float(mph*1.609344) 
     print(mph, 'Miles/Hour are equivalent to ', result, 'Kilometers/Hour') 
     print('----------------------------------------------------------------') 
def kph_to_mph(): 
     kph=eval(input('Amount of Kiometers per hour: ')) 
     result= float(kph*0.62137119) 
     print(kph, 'Kilometers/Hour are equivalent to ', result, 'Miles/Hour') 
     print('----------------------------------------------------------------') 
def exit_function(): 
    print('Thanks for using the conversion program.') 
    print('----------------------------------------------------------------') 
    import sys 
    sys.exit() 


def menu(): 
    print('----------------------------------------------------------------') 
    print('Welcome to the unit conversion program. Please select an option.') 
    print('1. Miles to Kilometers') 
    print('2. Kilometers to miles') 
    print('3. Pounds to Kilograms') 
    print('4. Kilograms to Pounds') 
    print('5. Celsius to Fahrenheit') 
    print('6. Fahrenheit to Celsius') 
    print('7. Miles/hour to Kilometers/hour') 
    print('8. Kilometers/hour to Miles/Hour') 
    print('9. Exit') 

screen=True 

while screen: 
    menu() 
    choice=eval(input('Enter option: ')) 
    if choice==1: 
     miles_to_km() 
    elif choice==2: 
     km_to_miles() 
    elif choice==3: 
     pounds_to_kg() 
    elif choice==4: 
     kg_to_pounds() 
    elif choice==5: 
     C_to_F() 
    elif choice==6: 
     F_to_C() 
    elif choice==7: 
     mph_to_kph() 
    elif choice==8: 
     kph_to_mph() 
    elif choice==9: 
     exit_function() 
    else: 
     print('Try a number between 1 and 9!') 

Answer 1

Vous pouvez convertir l'entrée avec l'instruction try.

while True: 
    menu() 
    choice = input('Enter option: ') 
    try: 
     choice = int(choice) 
    except ValueError: 
     print('invaild choice.') 
     print('Try a number between 1 and 9!') 
     continue 
    if choice==1: 
     miles_to_km() 
    elif choice==2: 
     km_to_miles() 
    elif choice==3: 
     pounds_to_kg() 
    elif choice==4: 
     kg_to_pounds() 
    elif choice==5: 
     C_to_F() 
    elif choice==6: 
     F_to_C() 
    elif choice==7: 
     mph_to_kph() 
    elif choice==8: 
     kph_to_mph() 
    elif choice==9: 
     exit_function() 
    else: 
     print('Try a number between 1 and 9!') 

Answer 2

while screen: 
    menu() 
while True: 
     try: 

    choice=eval(input('Enter option: ')) 
    if choice==1: 
     miles_to_km() 
    elif choice==2: 
     km_to_miles() 
    elif choice==3: 
     pounds_to_kg() 
    elif choice==4: 
     kg_to_pounds() 
    elif choice==5: 
     C_to_F() 
    elif choice==6: 
     F_to_C() 
    elif choice==7: 
     mph_to_kph() 
    elif choice==8: 
     kph_to_mph() 
    elif choice==9: 
     exit_function() 
    else: 
     print('Try a number between 1 and 9!') 

Answer 3

entrée

() renvoie toujours une chaîne. Ainsi, vous pouvez écrire une fonction d'aide comme ceci:

def input_int(message): 
    while True: 
     try: 
      number = int(input(message)) 
      return number 
     except ValueError: 
      print('Invalid number string, try again') 
      continue 

Une aide analogue pourrait input_float, etc.

Il ne fait aucun doute un paquet Python avec plus de cloches et de sifflets, si vous en avez besoin.