Python If-Then-Else Statement

In the previous article, you learned about the $if-block$ and how it executes statement if the condition for the $if$ is true. But we have not discussed anything about what should happen when $if-block$ is false.

The python programming language have a separate block of code to execute when the $if-block$ is false. It is called the $else-block$ . Consider the following diagram. In the figure, if the condition is true, execute $block \hspace{3px} A$ (also call it $if-block$ ) and if the condition is false, execute $block \hspace{3px} B$ .

Example – if-then-else

Let us take out previous example of $cash \hspace{3px} available$ to purchase an item with $price$ and $tax$ . If the $price \hspace{3px} + \hspace{3px} tax$ is less than the $cash \hspace{3px} available$ , a purchase can be done. Otherwise, customer cannot buy the item.

# Declaring cash available for purchase
cashAvailable = 5000
# price of item with tax 
price = 5000
tax = 200
# The if-block executes if the price + tax is less than or equal to cash
if cashAvailable >= price + tax:
     print("Purchase Successful", price + tax)
# The else will tell what to do if cash available is less 
else:
     print("Insufficient Cash ! Purchase cannot be done!")
print("Transaction Complete!")

The output of the program will be as follows.

Insufficient Cash! Purchase cannot be done!
Transaction Complete!

The program first check if $price \hspace{3px} + \hspace{3px} tax$ is less than the cash available. It is not true because the total amount is $5200$ . Therefore, the program jumps into the second block. the else block and prints $"Insufficient \hspace{3px} funds"$ . Note the indentation for the else block also. All line within a block has the same indentation.