In input, I want just numbers and not strings!

[aquerci]

Hi guys,

I have a simple question for you. Why the "input" function reads always the user input like a string? could not be it a problem?

right now I'm writing a simple script, but before to start, it must check if the user input is a number (int/float) or not. if the user input is a number it's ok, the script can start, otherwise it can't go ahead. How can I do that if Python read all the user inputs like a string? what is the discriminating factor to understand if the user input is a number or not?

p.s.:
I'm not an English speaker and I don't know very well Python, I'm still studying. Currently I'm reading the free book "Think in Python" by Allen B. Downey. I read just the first five chapters.

---

just to inform you, I'm using Python 3.6.6 in Linux Mint 19 Cinnamon.

[Larz60+]

import string,
check if input isdigit:

if entry.isdigit():
    ...

if so convert to integer

[DeaD_EyE]

The return type of input is always str. If you expect an integer or a float, use try/except in combination with int()/float().

def input_integer(question):
    while True:
        value = input(question)
        try:
            integer = int(value)
        except ValueError:
            print('Value "{}" is not a valid integer.'.format(value))
            continue
        return integer

def input_float(question):
    while True:
        value = input(question)
        try:
            float_value = float(value)
        except ValueError:
            print('Value "{}" is not a valid float.'.format(value))
            continue
        return float_value

value1 = input_integer('Please enter a valid integer: ')
value2 = input_float('Please enter a valid float: ')

The example functions asking for the value until you enter a valid value.

Checking if the input is an integer is not complicated,
but to check if the str is a valid float is more complex.