Python If Statement

The Python If statement is one of the most useful decisions making statements in real-time programming.

Python If statement allows the Python compiler to test the condition first, depend upon the result, it executes the code block. If a given test condition is true, then only statements within the if statement block executes.

Python If Syntax

The if statement in Python Programming has a simple structure:

if (test condition):
        Statement 2
        Statement 3
        ………….
        ………….
        Statement n

NOTE: Once you hit the enter after the semicolon, Python starts the next statement with a Tab space. This Tab space acts as {} (curly braces) in other languages.

From the above code, If the test condition in the Python If statement is true, the statements (Statement 1, Statement 2, ……., Statement n) will execute. Otherwise, all these statements will skip. Let us see the flow chart for a better understanding.

TIP: By clicking backspace, one can exit from the If statement

Python If Statement Flow Chart

If a test condition is true, STATEMENT 1 executed, followed by STATEMENT N. If it is False, STATEMENT N executes. Because it’s out of the if block and has nothing to do with the result.

Python If Statement Example

This program will check for the positive number using Python if. First, please open your favorite IDLE to write Python script, and here we are using Python 3.5.0.

Once you open Python IDLE, Please select the New File as shown in the below screenshot or else click Control + N

Once you click on the New File, a new file window will open to write a script for Python If example. Please add the below script in that new file

# Example for Python If Statement

number = int(input(" Please Enter any integer Value: "))
if number >= 1:
    print(" You Have Entered Positive Integer ")

Once completed, Click on the File, and select Save option

Please save the file as per you wanted

Let’s run the script by selecting Run Menu, and clicking the Run Module or press F5

Click the Run Module will pop up Python shell with the message, “Please Enter any integer Value:”. From the below screenshot, see that we entered 20 and it is a positive integer

OUTPUT

ANALYSIS

First, we declared a number variable and asked the user to enter any integer value. int() restrict the user not to enter non-integer values

number = int(input(" Please Enter any integer Value: "))

If you look at the below Python if statement, If Value stored in the number variable is greater than or equal to 0, the statement will be executed.

if number >= 1:
    print(" You Have Entered Positive Integer ")

Here we entered 20, which is greater than 0 that’s why it printed the statement inside the If statement block.

Python If Statement Example 2

In this Python if statement example, we will show you what happens to the statements outside the If block. To demonstrate this, we altered the example 1 and added the following code.

# Example for Python If Statement

number = int(input(" Please Enter any integer Value: "))
if number >= 1:
    print(" You Have Entered Positive Integer ")
print(" This Message is not coming from PYTHON IF STATEMENT")

If you observe the above Python If statement code, it is the same code that we used in the first example. However, this time, we added one more print statement outside the If statement block with the message This Message is not coming from PYTHON IF STATEMENT

Let us run the Code. From the below screenshot, you can observe that we entered 50, it means If condition is TRUE. So, Python is displaying print statement inside the If statement and Outside the If block

Let’s try the negative values to intentionally fail the Python If condition

If the condition failed here (number < 1). compiler prints nothing from the Python If condition block. So, it printed only one print statement, which is outside the block.