Question

Hello Admin: Make a list of five or more usernames, including the name 'admin'. Imagine you are writing code that will print a greeting to each user after they log in to a website. Loop through the list, and print a greeting to each user: \- If the username is 'admin', print a special greeting, such as Hello admin, would you like to see a status report? \- Otherwise, print a generic greeting, such as Hello Eric, thank you for logging in again.

Short answer

Create a list of usernames including 'admin', loop through them, print a special message for 'admin' and a generic greeting for others.

Step-by-step solution

Create Usernames List

Start by creating a list in your code that contains the usernames. Ensure that the list includes the name 'admin' along with other user names. For example: ``` usernames = ['admin', 'Eric', 'Jessica', 'Tom', 'Ashley'] ```

Initiate a Loop Through Usernames

Create a loop to iterate through each username in the list. This can be done with a `for` loop. For instance: ``` for username in usernames: ```

Check for 'admin'

Within the loop, use an `if` statement to check if the current username is 'admin'. If it is, print a special greeting. For instance: ``` if username == 'admin': print('Hello admin, would you like to see a status report?') ```

Print Greeting for Other Users

If the current username is not 'admin', use an `else` statement to print a generic greeting for the user. For example: ``` else: print(f'Hello {username}, thank you for logging in again.') ```

End the Loop

Let the loop iterate over all usernames, and it will print the appropriate greeting for each. No further action is needed to end the loop explicitly in Python.

Key concepts

Conditional Statements

Conditional statements in Python allow the programmer to make decisions based upon different conditions to control the flow of the application. They usually take the form of `if`, `elif`, and `else`.

• If Statement: The basic decision-making structure. It executes a block of code if a specified condition is evaluated as True.
• Else Statement: Follows an `if` statement and executes a block of code if the preceding `if` condition is False.
• Elif Statement: Combines `else` and `if`, allowing multiple conditions to be checked after an initial `if` condition.

In our exercise, we use the `if-else` structure to determine whether the current user is 'admin'. If so, we offer a special message. If not, a generic greeting is displayed. This showcases how conditional statements can dynamically alter program responses based on input.

List Manipulation

List manipulation refers to modifying or working with lists to perform various operations. Lists in Python are versatile and can hold multiple items.

• Creating Lists: For the exercise, a list of usernames is created using square brackets.
• Iterating Through Lists: This involves accessing and performing operations on each element in the list using loops.

In our example, the list `usernames` contains users including 'admin'. The loop iterates over this list, allowing us to perform checks and print greetings based on each element. List manipulation enables us to organize data and perform bulk operations efficiently.

String Formatting

String formatting is a way to dynamically create strings by inserting values into them. In Python, this is often done using f-strings, which were added in Python 3.6.

• F-Strings: These are prefixed with `f` and allow you to include variables within curly braces directly in your string.
• Advantages: F-strings offer a readable and concise syntax, making it easier to construct strings by embedding expressions inside string literals.

In our code example, the command `f'Hello {username}, thank you for logging in again.'` is used. This replaces `{username}` with the current user's name within the loop, personalizing each greeting. This powerful tool ensures your strings are flexible and contextually appropriate without verbose concatenations.

Control Flow in Programming

Control flow dictates the order in which instructions are executed in a program. It is a fundamental concept involving conditional executions and iterations.

• Loops: Allow repeated execution of a code block. Here, `for` loop iterates over the `usernames` list.
• Decisions: Made using conditional statements like `if-else`, affecting which parts of the code run under specific circumstances.

In our exercise, the program uses a `for` loop to automate the greeting process for each user. The control flow, enforced by the loop and conditions, makes it possible to tailor responses for different users. This automation vitalizes the program, reducing manual effort while maintaining scalability and adaptability when handling more users or different conditions in future scenarios.