The Python If statement is one of the most useful decision making statements in real-time programming. It allows the compiler to test the condition first and then, depending upon the result it will execute the statements. If the test condition is true then only statements with in the if statement block is executed.
Python If Statement Syntax
The If statement in Python Programming has simple structure:
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if (test condition): Statement 2 Statement 3 …………. …………. Statement n |
NOTE: Once you hit the enter after semicolon, python will start the next statement with Tab space and this Tab space acts as curly braces ({ }) in other programming languages.
From the above code, If the test condition in the If statement is true, then the statements (Statement 1, Statement 2, Statement 3, ……., Statement n) will be executed, otherwise all these statements will be skipped. Let us see the flow chart for better understanding.
TIP: By clicking backspace you can exit from the If statement block
Python If Statement Flow Chart
Python If Statement Example
This program will check for the positive number using Python if statement. 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 simply click Control + N
Once you click on the New File, new file window will be opened to write Python script. Please add the following script in that new file
PYTHON CODE
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# Example for Python If Statement number = int(input(" Please Enter any integer Value: ")) if number >= 1: print(" You Have Entered Positive Integer ") |
Once you are done, Click on the File Menu and select Save option as shown below
Please save the file as per your requirements
Once you save the file, Let us run the script and see by selecting Run Menu and click on Run Module or simply click F5
Once you click on Run Module, Our Python shell will pop up with message “Please Enter any integer Value:” . From the below screenshot you can observe that we entered 20 and it is positive integer
OUTPUT
ANALYSIS
First, we declared number variable and asks the user to enter any integer value. int() restrict the user not to enter non integer values
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number = int(input(" Please Enter any integer Value: ")) |
If you look at the below if statement, If Value stored in the number variable is greater than or equal to 0 then the print statement will be executed.
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if number >= 1: print(" You Have Entered Positive Integer ") |
Here we entered 20, which is greater than 0 that’s why it printed (print statement) inside the If statement block.
Python If Statement Example 2
In this example we will show you, what happens to the statements outside the If Statement block. To demonstrate this, we altered the example 1 and added following code to the python script
PYTHON CODE
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# 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 code, it is same code we used in the first example but 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 script is displaying print statement inside the If statement and Outside the If block
Let’s try the negative values to deliberately fail the condition
If condition failed here (number < 1). It print nothing from the If condition block so it printed only one print statement which is outside the statement block.
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