Python during runtime does not consider a number entered as a int or float

Question

I am a beginner and it might feel like a silly question.

I am trying to create a simple program,a temperature converter from Celsius to F*.

Which takes:

'quit' for stopping program
int values for providing the correct result

Problem: any text value entered by user is handled through try expect error and a while loop which ask them to enter the int value again, but the second time user enters a correct value (which is int) the system considers it as a string and the loop is never ending.

Here is my program:

# Program to convert Celsius to Fahrenheit

import time

while True:

    userinput= input(" 1 Enter the temperature in celsius: "
                 "Enter Quit if you want to close the converter")

    if userinput.lower()=='quit':
        print('Closing the application. Thanks for using the converter')
        break

    try:
        userinput= float(userinput)

    except ValueError:
        print('You cannot enter text, please use numbers')
        while userinput.lower()!='quit':

            if type(userinput)!=str:
                userinput = float(userinput)
                print(type(userinput))

                break
            else:
                while type(userinput)==str:

                    userinput = (input(" 2. Oops Enter the temperature in celsius: "
                              "Enter Quit if you want to close the converter"))
                    print(type(userinput))
                    ## my problem is here even if enter a integer 2 as userinput. i  am getting the type userinput as str. Can someone help me

    type(userinput)
    userinput=float(userinput)
    f=userinput*9.0/5+32
    print('Your input was:',userinput,'\n'*2,'The corresponding Fareinheit is',f,'\n'*3, '---'*25)

Can't reproduce, it works for me. I would recommend just using `continue` in the except clause. — L3viathan, Sep 14 '16 at 18:21
In Python 3.x `input` returns a str, in Python 2.x `input` returns an int — MooingRawr, Sep 14 '16 at 18:22
Can you enter two times ' temperature' instead of an integer into this program? — begineer, Sep 14 '16 at 18:27

Dinesh Pundkar · Answer 1 · 2016-09-14T19:08:43.447

Code after print('You cannot enter text, please use numbers') is not required. Due this code, it is stucked in infinite loop once you enter wrong input

Since input is asked in while loop, user input will be asked though the wrong input is given.

Code (Check comments):

while True:
#Get input
userinput= input(" 1 Enter the temperature in celsius: "
                 "  Enter Quit if you want to close the converter")
#Check user wants to quit
if userinput.lower()=='quit':
    print('Closing the application. Thanks for using the converter')
    break

try:
    #Check type of userinput
    print "Type is =",type(userinput)
    #Check user input is number
    userinput= float(userinput)
    f=userinput*9.0/5+32
    print('Your input was:',userinput,'\n'*2,'The corresponding Fareinheit is',f,'\n'*3, '---'*25)

except ValueError:
    #If user input is not number, then print error message.
    #After this, again user input will be asked due to while loop.
    print('You cannot enter text, please use numbers')

Output:

  C:\Users\dinesh_pundkar\Desktop>python c.py
 1 Enter the temperature in celsius:   Enter Quit if you want to close the conve
rter"57"
Type is = <type 'str'>
('Your input was:', 57.0, '\n\n', 'The corresponding Fareinheit is', 134.6, '\n\
n\n', '-------------------------------------------------------------------------
--')
 1 Enter the temperature in celsius:   Enter Quit if you want to close the conve
rter"asd"
Type is = <type 'str'>
You cannot enter text, please use numbers
 1 Enter the temperature in celsius:   Enter Quit if you want to close the conve
rter"34"
Type is = <type 'str'>
('Your input was:', 34.0, '\n\n', 'The corresponding Fareinheit is', 93.2, '\n\n
\n', '--------------------------------------------------------------------------
-')
 1 Enter the temperature in celsius:   Enter Quit if you want to close the conve
rter"quit"
Closing the application. Thanks for using the converter

C:\Users\dinesh_pundkar\Desktop>

Also, if you are using Python 2, then use raw_input instead of input. For Python 3 input works.

Of the flurry of answers to this question, only this one makes any sense. Crazy! :P — roganjosh, Sep 14 '16 at 18:47
Thanks for the the help Dinesh. I know I unnecessarily wrote 3 loops but my question. Your answer was perfect from a learning perspective. But only question i have is hile type(userinput)==str: userinput = (input(" 2. Oops Enter the temperature in celsius: " "Enter Quit if you want to close the converter")) print(type(userinput)) why does a integer entered is showing us string type? — begineer, Sep 14 '16 at 18:48
@begineer `input` will always be a string, and there's no need to have a nested `while` loop. Let the main loop fail and it just starts again. You cannot test for whether or not a temperature for in Celsius, it's an unbound scale (except for absolute zero) — roganjosh, Sep 14 '16 at 18:52
@begineer - roganjosh is correct that input will always string. I have updated my code. It will give you example of what roganjosh has explained. Check the line - Type is in output. It will give type of userinput. — Dinesh Pundkar, Sep 14 '16 at 19:11

score 0 · Answer 2 · answered Sep 14 '16 at 18:21

0

Not sure if I understand the problem correctly, but usually it is better to use raw_input instead of input in case like this.

answered Sep 14 '16 at 18:21

jhutar

1,369
2
17
32

2

Unless they use Python 3, in which case `raw_input` doesn't exist – roganjosh Sep 14 '16 at 18:22
Right, was too quick to judge. Main problem was the second while :) – jhutar Sep 14 '16 at 18:39
I agree. Jhutar – begineer Sep 14 '16 at 19:01

score 0 · Answer 3 · answered Sep 14 '16 at 18:25

You are using three nested while loops here for no obvious resons. When the user enters a wrong value, he gets transferred to the next while loop which never ends. This is a quick and dirty solution.

# Program to convert Celsius to Fahrenheit

import time

while True:

    userinput= input(" 1 Enter the temperature in celsius: "
                 "Enter Quit if you want to close the converter")

    try:
        userinput= float(userinput)
        type(userinput)  
        userinput=float(userinput)
        f=userinput*9.0/5+32
        print('Your input was:',userinput,'\n'*2,'The corresponding Fareinheit is',f,'\n'*3, '---'*25)


    except ValueError:
        print('You cannot enter text, please use numbers')        

        if userinput.lower()=='quit':
            print('Closing the application. Thanks for using the converter')
            break

score 0 · Answer 4 · edited May 23 '17 at 12:01

0

the problem is here:

if type(userinput)!=str:

since input returns a string, userinput is always a string: Thus, the above snippet is always false. you should try parsing it as a float like in this answer

edited May 23 '17 at 12:01

Community

1
1

answered Sep 14 '16 at 18:26

Adalcar

1,458
11
26

score 0 · Answer 5 · answered Sep 14 '16 at 18:29

In the 1 input, you cast it, in the second one, you never cast.

I also noticed, you never actually implemented the "quit" functionality for that loop. This should make your code a bit easier to read.

def checkToClose(value):
  if (value.lower() == 'quit')
    quit()

while True:
  userinput= input(" 1 Enter the temperature in celsius: "
             "Enter Quit if you want to close the converter")

  checkToClose(userinput)

  try:
    userinput= float(userinput)
  catch:
    continue

  f = userinput * 9.0 / 5 + 32
  print('Your input was:',userinput,'\n'*2,'The corresponding Fareinheit is',f,'\n'*3, '---'*25)

Fixing the syntax errors in this and accounting for Python 2/3 compatibility issues, this doesn't work. There is no `catch` in Python, it's `except` but even then, why would you `continue` into a failing calculation? — roganjosh, Sep 14 '16 at 18:37

Python during runtime does not consider a number entered as a int or float

5 Answers5