Question

What would the following code display? if 'z' < 'a': print('z is less than a.') else: print('z is not less than a.')

Short answer

Answer: The output of the provided code snippet will be "z is not less than a."

Step-by-step solution

Understand the code structure

The code contains an if-else statement, used for making a decision based on the comparison of two characters, 'z' and 'a'. If 'z' is less than 'a', the first block will be executed, otherwise the second block will be executed.

Comparison of the characters

In Python, when characters are compared using comparison operators (like <, >, ==, etc.), their ASCII (or Unicode) values are used for the comparison. The character 'z' has an ASCII value of 122 and 'a' has an ASCII value of 97. Therefore, 'z' is not less than 'a'.

Determine the executed block

Since 'z' is not less than 'a', the condition in the if statement is false. Therefore, the code inside the else block will be executed.

Output of the code

As the else block is executed, the output that will be displayed is: "z is not less than a." Now that we have thoroughly analyzed the provided code snippet, we can conclude that when the given code is executed, it will display "z is not less than a." as its output.

Key concepts

if-else Statement in Python

Understanding the if-else statement is essential for controlling the flow of a Python program. It lets you execute certain code only when a specific condition is true and other code when that condition is false. It's structured with an if keyword, a condition that evaluates to either true or false, an optional else keyword, and the code to execute for each scenario.

Here's a simple way to think about it: imagine deciding what to wear. If it's raining (the condition), you might choose to wear a raincoat (the code after the if). Otherwise (the else), you might wear a t-shirt. In Python, you would write this decision-making process using an if-else statement like this:
if is_raining:
  wear('raincoat')
else:
  wear('t-shirt')

Similarly, in the given exercise, we used this structure to decide which message to print based on the comparison of characters 'z' and 'a'.

Character Comparison in Python

When comparing characters in Python, you might wonder how Python determines which character is 'greater' or 'less' than another. Python uses the ASCII values of characters to make this comparison. Let's break it down:

• Each character on your keyboard corresponds to a unique number based on the ASCII standard.
• When you compare two characters, Python doesn't look at their order in the alphabet; it looks at their associated ASCII values.
• A comparison like 'z' < 'a' is asking whether the ASCII value for 'z' is less than the ASCII value for 'a'.

In our exercise, we used this concept to determine the output of the program. Knowing that 'z' has a higher ASCII value than 'a', the comparison 'z' < 'a' would evaluate as false, leading the else block to execute.

ASCII Values in Python

You've seen ASCII values mentioned a couple of times now, but what are they? ASCII values are numeric representations of characters. ASCII, which stands for American Standard Code for Information Interchange, assigns each character a unique number. These numbers are used internally by computers to represent text.

For instance:

• The character 'a' has an ASCII value of 97.
• The character 'z' has an ASCII value of 122.

These values allow computers to sort and compare characters in a consistent manner. When you instruct Python to compare 'z' with 'a', it compares their ASCII values, 122 and 97 respectively, and follows the logic designed in your code. This concept underpins the character comparison in our exercise, showing why 'z' is not considered less than 'a'.