if the input is not number, let user input again

[teatea]

hi :) i am starting to learn python, and learning from Automating Boring Stuff With Python, then i tried to implement the knowledge and do something by myself.

i am creating this program that asks user for the age. when i tested the program, i realised if i didn't enter the number correctly as integer, the program would not continue.

so i tried to create a condition for the program to check whether it is integer or not, if not, the user can type again, and then the program would print 'thank you', and continue to print the calculated value, and continue until the end.

however, i am caught up for a lengthy period, so i think i should post a question to ask someone knowledgeable, here are my codes :

 print('hello there') print('what is your name?') myName = input() print('your name is ' + myName + ', it is nice to meet you') print('the length of your name is composed of ' + str(len(myName)) + ' letters.') print('what is your age?') myAge = input(int()) if myAge == input(int()): print('thank you') else: print('please enter the number only') while myAge != int(): print('please enter the number only') myAge = input(int()) print('thank you') print('you will be ' + str(int(myAge) + 1) + ' next year') print('this is the end of this program')

thank you :)

[Gribouillis]

This is a very common question. At the same time, the answer is not obvious because it forces you to use the exceptions mechanism.
Here is one way to do it

while True: try: age = int(input("How old are you? ")) except ValueError: print("Invalid value. Please enter an integer! Let's try again...") else: break print("You are {} years old.".format(age))

[DPaul]

if you do

input('What is your age? ')

You will get a string.
To test if this string is a number with int(),you might look into try / except / finally clauses.
This way you program will not crash when int() fails.

(But there are many other ways)
Paul

[teatea]

thank you so much!!!

i am loving the program :) feels so good that it finally runs!!!

[menator01]

Your missing except for the first try statement

[menator01]

Another way. Modified code a little.

#! /usr/bin/env python3.8 while True: try: my_name = input('What is your name: ') if my_name.isdigit(): print(f'{my_name} is a number. Please use letters for a name.') continue else: print(f'Your name is {my_name}. It\'s nice to meet you') print(f'The length of your name is {len(my_name)} letters.') break except ValueError as error: print(f'Error: {error}') break while True: try: my_age = input(f'{my_name.title()}, what is your age: ') if my_age.isalpha(): print(f'{my_age} is not allowed in age') continue else: age = int(my_age) + 1 print(f'{my_name.title()} will be {age} next year.') break except ValueError as error: print(f'Error: {error}') break

Output:
What is your name: john Your name is john. It's nice to meet you The length of your name is 4 letters. John, what is your age: p p is not allowed in age John is your age: 15 John will be 16 next year.

[menator01]

Updated code to check for floats May not be best method but, works

#! /usr/bin/env python3.8 while True: try: my_name = input('What is your name?: ') if my_name.replace('.','').isdigit(): print(f'{my_name} is a number. Please use letters for a name.') continue else: print(f'It\'s nice to meet you {my_name.title()}') print(f'{my_name.title()}, your name is {len(my_name)} letters long.') break except ValueError as error: print(f'Error: {error}') break while True: try: my_age = input(f'{my_name.title()}, what is your age?: ') if my_age.isalpha(): print(f'{my_name.title()}, {my_age} is not a number.') continue else: age = int(my_age) + 1 print(f'{my_name.title()}, you will be {age} next year.') break except ValueError as error: print(f'Error: {my_name.title()}, please only use whole numbers for age.') continue

Output:
What is your name?: 15.3 15.3 is a number. Please use letters for a name. What is your name?: john It's nice to meet you John John, your name is 4 letters long. John, what is your age?: pop John, pop is not a number. John, what is your age?: 15 John, you will be 16 next year.

[GOTO10]

this programme work perfect but when i enter my name like 15.1 (float) is says:

Output:
What is your name: 15.1 Your name is 15.1. It's nice to meet you The length of your name is 4 letters. 

is this float is not a digit ?

The isdigit() method only returns True if every character in the string is a digit. The '.' in a float value is not a digit, so isdigit() returns False for a float. You can use isalpha() to make sure all of the characters are letters, or you could use isalpha() and istitle() together to ensure the first letter is capitalized. (You could also just use istitle() in your print statement like menator01 does.)

while True: my_name = input('What is your name? ') if not my_name.isalpha(): print('Please use only letters for your name.') continue else: print(f'Your name is {my_name}.') print('The length of your name is', len(my_name), 'characters.') break while True: try: my_age = int(input(f'What is your age, {my_name}? ')) print('Your age is ' + str(my_age) + '.') print('You will be ' + str(my_age + 1) + ' in one year.') break except ValueError: print('Please use only whole numbers for your age.') continue

[BitPythoner]

Use try and except in the following manner.

try:
Code to be ran if user entered int
except:
Code to be ran if user did not enter integer.

[pyzyx3qwerty]

@ibutun also remember, if you have a question, please do not post it in a thread start by another person - start your own thread. Please do that in the future