Lab
A Cloud Guru

Using Python Conditional Expressions

We need to constantly evaluate a condition of some kind to determine what action to take or what value to assign to a variable we'll use later in our program. In the situation where we only have an `if` and an `else`, and the body of each branch contains only one expression, then we're able to use a conditional expression. Conditional expressions can be used to succinctly express a simple conditional. In this hands-on lab, we'll be refactoring an existing script by rewriting the simple conditional statements as conditional expressions. The following is a prerequisite for feeling comfortable completing this lab: - Conditional expressions.

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Path Info

Level

Beginner

Duration

30m

Published

Mar 20, 2020

Challenge

Call `print` with a Different String Using a Single Conditional Expression
Our first conditional statement checks the length of the name passed in and prints a different message depending on that length. We've been tasked with writing a conditional expression that calls one of these print functions if true and the other if false.

process_name.py
```
name = input("What is your first name? ")

# 1) Call `print` with a different string using a single conditional expression
# 1) Call `print` with a different string using a single conditional expression
print(
    "Your name is as long or longer than the average first name in the United States"
) if len(name) >= 6 else print(
    "Your name is shorter than the average first name in the United States"
)
```
These messages are pretty long, so it makes it easier to read if we spread this expression across multiple lines. However, we are still running only one expression.
Challenge

Assign a Value to the `message` Variable Based on a Conditional Expression
Each branch for our next conditional statement assigns a value to the message variable. Because of this, we can assign the value returned by a conditional expression directly to the message variable.

process_name.py
```
# 2) Set `message` using a single conditional expression
message = (
    "The first letter in your name is among the five most common"
    if name[0].lower() in ["a", "j", "m", "e", "l"]
    else "The first letter of your name is not among the five most common"
)

print(message)
```
The strings that we might assign to message are fairly long, but we can spread this expression across multiple lines by wrapping the entire expression in parenthesis.
Challenge

Change the String Passed to the `print` Function Using a Conditional Expression
We want to change the string that is printed as we iterate over all of the letters in our name variable. The portion of the printed message that is different based on the letter is at the end. We can utilize a conditional expression from within the print function instead of having two separate print lines.

process_name.py
```
# 3) Change the string passed to the `print` function using a conditional expression
for letter in name:
    print(
        f"{letter} {'is a vowel' if letter.lower() in ['a', 'e', 'i', 'o', 'u'] else 'is a consonant'}"
    )
```

Author

A Cloud Guru

The Cloud Content team comprises subject matter experts hyper focused on services offered by the leading cloud vendors (AWS, GCP, and Azure), as well as cloud-related technologies such as Linux and DevOps. The team is thrilled to share their knowledge to help you build modern tech solutions from the ground up, secure and optimize your environments, and so much more!

What's a lab?

Hands-on Labs are real environments created by industry experts to help you learn. These environments help you gain knowledge and experience, practice without compromising your system, test without risk, destroy without fear, and let you learn from your mistakes. Hands-on Labs: practice your skills before delivering in the real world.