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Kenil Vasani
Kenil Vasani

Kenil Vasani

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Asked: 2020-12-11T20:38:24+00:00 In:

Python – TypeError – TypeError: ‘<' not supported between instances of 'NoneType' and 'int'

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TypeError: ‘<‘ not supported between instances of ‘NoneType’ and ‘int’

I have looked for an answer in Stack Overflow and found that I should be taking an int(input(prompt)), but that’s what I am doing 

def main():      
while True:
        vPopSize = validinput("Population Size: ")
        if vPopSize < 4:
            print("Value too small, should be > 3")
            continue
        else:
            break

def validinput(prompt):
while True:
    try:
        vPopSize = int(input(prompt))
    except ValueError:
        print("Invalid Entry - try again")
        continue
    else:
        break
python
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    1 Answer

    1. Rohit Patel

      Rohit Patel

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      Best Answer

      This problem also comes up when migrating to Python 3.

      In Python 2 comparing an integer to None will “work,” such that None is considered less than any integer, even negative ones:

      >>> None > 1
False
>>> None < 1
True

      In Python 3 such comparisons raise a TypeError:

      >>> None > 1
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: '>' not supported between instances of 'NoneType' and 'int'

>>> None < 1
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: '<' not supported between instances of 'NoneType' and 'int'
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