Python Program to Check if a Number is Positive, Negative or 0

In this tutorial, you will create a Python program to check if a number is positive, negative, or 0.

You can check this by checking if the number is greater than 0 or less than 0.

If a number is greater than 0 then it will be positive.

But if a number is less than 0 it will be negative.

If you are new to Python, to understand this code, you should first check:

• How to get basic input and output in Python
• If and else conditional statements in Python
• While loop in python

Simple Code

num = input('Enter a number to check its nature : ')
num = float(num)
if num > 1:
    print('Positive.')
elif num < 1:
    print('Negetive.')
elif num == 0:
    print('zero')

Code with exception handling

while True:
    try:
        num = input('Enter a number to check its nature : ')
        num = float(num)
        if num > 1:
            print('positive')
        elif num < 1:
            print('negetive')
        elif num == 0:
            print('zero')
        break
    except:
        print('Invalid entry.')

Output

Enter a number to check its nature : 59
Positive.

Code with explanation

#take input from the user
        num = input('Enter a number to check its nature : ')
        #Convert the input to float, may be  user entered some float value (This will work fine for integers as well)
        num = float(num)
        
        #checking if number is greater than 1, print Positive.
        if num > 1:
            print('positive')
        #if the number is not greater than one, then check if it is less than one. If so, print negative
        elif num < 1:
            print('negetive')
        #If first two conditions are wrong then check if it is equal to zero
        elif num == 0:
            print('zero')

Code with explanation (Exception handling)

#program will run until it is executed successfully!
while True:
    #This try block will be executed first and if the user enter an interger, the result will be printed and program will end successfully
    #But if the user enter wrong input such as an alphabet, program will throw an error and will run again
    try:
        #take input from the user
        num = input('Enter a number to check its nature : ')
        #Convert the input to float, may be  user entered some float value (This will work fine for integers as well)
        num = float(num)
        
        #checking if number is greater than 1, print Positive.
        if num > 1:
            print('positive')
        #if the number is not greater than one, then check if it is less than one. If so, print negative
        elif num < 1:
            print('negetive')
        #If first two conditions are wrong then check if it is equal to zero
        elif num == 0:
            print('zero')
        #this break command will end the program if it is executed successfully.
        break
    
    #But in some cases, the user may enter some alphabet or any other character. Then this error will be displayed and loop will run the program again
    except:
        print('Invalid entry.')