Check if a number is positive, negative or zero in Python

Three possible answers need three branches: if, elif and else.

The program

n = float(input("Enter a number: "))

if n > 0:
    print("Positive")
elif n < 0:
    print("Negative")
else:
    print("Zero")

Typed in this example: -3.5. Press Run to type your own.

Enter a number: -3.5
Negative

How it works

• Python checks the conditions from top to bottom and runs only the first branch whose condition is true.
• elif means "else if": it is only checked when the if above it was false.
• else catches everything left. If a number is not more than 0 and not less than 0, it must be 0, so no third test is needed.
• float() means the program accepts decimals such as -3.5 as well as whole numbers.