python input error checking

Question

Hello, I am trying to get my input to only allow integers, and once it gets past 10, it displays error, any assistance would be appreciated.

square_ct = input("Enter an integer from 1-5 the number of squares to draw: ")
triangle_ct = input("Enter an integer from 1-5 the number of triangles to draw: ")

while square_count(input) > 10:
    print ("Error!")
    square_count=input() #the statement reappears

while triangle_count(input) > 10:
    print ("Error!")
    triangle_count=input() #the statement reappears

nneonneo · Accepted Answer · 2012-09-16 01:55:52Z

3

My preferred technique is to use a while True loop with a break:

while True:
    square_ct = input("Enter an integer from 1-5 the number of squares to draw: ")
    if square_ct <= 10: break
    print "Error"

# use square_ct as normal

Or, on Python 3:

while True:
    square_ct = int(input("Enter an integer from 1-5 the number of squares to draw: "))
    if square_ct <= 10: break
    print("Error")

# use square_ct as normal

edited Sep 16, 2012 at 1:55

answered Sep 16, 2012 at 0:18

nneonneo

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4 Comments

Ryan Tice Over a year ago

So should I do two separate while true statements for each of the questions? I am getting error TypeError: unorderable types: str() > int()

nneonneo Over a year ago

I suspected as much, but the way he was using input (without converting to int) made it look like Python 2.x.

DSM Over a year ago

Am I the only one who thinks it's strange that the text says "enter an integer from 1-5", but the test only involves 10? (Just a detail, of course.)

nneonneo Over a year ago

Yep, I noticed it. Not the weirdest thing I've seen on SO; I'm sure the asker will figure it out.

Norm · Accepted Answer · 2021-11-24 01:56:32Z

I took the path nneonneo offered and got pretty close to what I wanted. The final result is below.

I thank all of you for your comments. The last time I did anything even slightly like programming was in Fortran on punch cards on an IBM 360.

I apologize for asking such basic questions but really am trying.

The code that works but really doesn't point out exactly which fault happened. I will try to figure out how to convert the string in the input statement to a float and see if there is a remainder (modulo maybe?) so the user gets a better hint what was wrong.

import math
from datetime import datetime
import time

num = 0
start = 0
end = 0

try:
   num = int(input('Enter a positive whole number: '))
   if (num >= 0 and num <= 2147483647):
       start = datetime.now()
       print("The factorial of ", num, " is : ")
       print(math.factorial(int(num)))
       end = datetime.now()
   else:
      print('Number must be between 0 and 2147483647 are allowed.')
      print(f"Time taken in (hh:mm:ss.ms) is {end - start}")
except ValueError:
    print('Text or decimal numbers are not allowed. Please enter a whole number between 0 and 2147483647')

I have a lot to learn because I'm bored...

Norman

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