Check on input Python 3.5.2

Question

Fahr = input("Insert temperature in Fahrenheit: " ) 

while type(Fahr) != float or type(Fahr) != int:

    Fahr = input("Error: Insert temperature in Fahrenheit: " )

Celcius = ((Fahr) - 32) * 5/9


print("Your imput: " + Fahr + " Fahrenheit" ) 

print("This is equal to: " + Celcius + " Celcius" )

I need to be sure that the user only inserts INT's or floats. When i execute this code, it goes automatically go in the while loop even when i insert an INT or float. Whats wrong with this code and how should it be?

`Fahr` will always be a string (`str`), that's what `input()` returns. — cdarke, Sep 22 '16 at 16:03
read this: http://stackoverflow.com/questions/354038/how-do-i-check-if-a-string-is-a-number-float-in-python — proton, Sep 22 '16 at 16:04
Or this: http://stackoverflow.com/questions/14566260/inputing-floats-integers-or-equations-in-raw-input-to-define-a-variable — cdarke, Sep 22 '16 at 16:05
I believe the solution is to use the `and` operator instead of the `or` operator. A number can't be both an integer and a float at the same time. — Fernando Karpinski, Sep 22 '16 at 16:06
Is this Python 2 or Python 3? `input()` has different functionality between the two, I was assuming python 3. — cdarke, Sep 22 '16 at 16:10
@cdarke, this is Python 3. I tested with Python 2, so maybe I was wrong. i updated my comment. — Fernando Karpinski, Sep 22 '16 at 16:11

Jeril · Answer 1 · 2016-09-22T17:00:33.037

0

Could you try with the following code:

def inp():
    try:
        Fahr = float(raw_input("Insert temperature in Fahrenheit: " ))
        return Fahr
    except Exception as e:
        return e

Fahr = inp()
while True:
    if 'could not convert' in str(Fahr):
        Fahr = inp()
    else:
        break

Celcius = ((Fahr) - 32) * 5/float(9)

print("Your input: " + str(Fahr) + " Fahrenheit" ) 
print("This is equal to: " + str(Celcius) + " Celcius" )

The following is the output:

>>> ================================ RESTART ================================
>>> 
Insert temperature in Fahrenheit: hello
Insert temperature in Fahrenheit: !@
Insert temperature in Fahrenheit: ()()((
Insert temperature in Fahrenheit: 10.5
Your input: 10.5 Fahrenheit
This is equal to: -11.9444444444 Celcius

edited Sep 22 '16 at 17:00

answered Sep 22 '16 at 16:07

Jeril

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It "will work fine" unless the user doesn't enter a number, and the OP said that they "need to be sure that the user only inserts INT's or floats," which this doesn't check for. – TigerhawkT3 Sep 22 '16 at 16:12
I have to print an error and let the user insert a new value, if he inserts a string. Sorry i am new to this site and its my first question. Thanks for the help! – M.Ince Sep 22 '16 at 16:15
I have edited the code. Kindly check. – Jeril Sep 22 '16 at 16:24
Hey Jeril, i tried this. Yes it works, but only for 1 time. So if i insert 2 times a string. The program crashes! – M.Ince Sep 22 '16 at 16:29
I have put a modified code, could you check? – Jeril Sep 22 '16 at 17:01
Amazing friend this worked perfectly! Thank u very much :) – M.Ince Sep 22 '16 at 17:07
Welcome friend... – Jeril Sep 23 '16 at 06:05

score -1 · Answer 2 · edited Sep 22 '16 at 16:14

-1

input() function always return a string. Convert to int or float first.

edited Sep 22 '16 at 16:14

vishes_shell

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answered Sep 22 '16 at 16:04

Jal

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Fahr = int(input("Insert temperature in Fahrenheit: " )) . I did this now but when i type a string it gives me: invalid literal for int() with base 10: 'df' – M.Ince Sep 22 '16 at 16:06
That is normal. You can catch this exception and retry the input in that case – 3Doubloons Sep 22 '16 at 16:09
This answer doesn't include anything to ensure that the user enters a number, which the OP requires. – TigerhawkT3 Sep 22 '16 at 16:15

Check on input Python 3.5.2

2 Answers2