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DO NOW

Complete the classroom scavenger hunt worksheet based on your observations.

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VARIABLES

IN

PYTHON

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Lesson Goals

UNDERSTAND THE PURPOSE OF VARIABLES

MASTER VARIABLE DECLARATION AND INITIALIZATION

CREATE VARIABLES IN PYTHON

1

2

3

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SCAVENGER HUNT REVIEW

DO NOW

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Scavenger Hunt Review

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What is a variable?

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“Imagine a variable as a box or basket in the world of programming. This box has a special ability – it can hold a value, just like a container can hold objects. In this case, the "value" is the information you want to keep safe and organized.

When you create a variable, it's like placing a label on your box, telling you what's inside. For example, you might have a box labeled "number_of_students," and inside, it holds the actual number of students in a class.

Now, imagine you can open this box, change what's inside, or even combine it with information from another box. This flexibility is what makes variables powerful. You can use these labeled boxes to store and manage different types of information, just like you would use different containers to organize items in your daily life.

So, in programming, a variable is like your labeled box or basket, helping you keep things in order and giving you the ability to work with the stored information in various ways.”

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DECLARING VARIABLES

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When we talk about declaring a variable in programming, think of it as creating a brand new, shiny box or basket. This box is your storage space, your digital container that can hold valuable information.

Now, here's the key: Just like in real life, it's crucial to have a clear label on your box. This label is what we call the 'variable name' in programming. It's like giving your box a name so you can easily recognize and remember what's inside. Imagine you're at home, and you have a box labeled 'Summer Clothes' – you instantly know what's in there without having to open it.

So, when we declare a variable, we're essentially making a new box for our program to use. And we're not just throwing any old name on it; we're giving it a meaningful label, a name that tells us what kind of information the box is going to hold. This way, when we come back to our code later on, we can quickly understand what each box is for and use the information inside effectively.

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Rules for declaring variables

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Begin with a letter or underscore� Letters, numbers, or underscores		Spaces Special Characters

Rules for declaring variables

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BE�DESCRIPTIVE

Another important aspect when naming variables in Python is making them descriptive. Imagine you're writing a story, and the characters have names that reflect their personalities or roles. Similarly, when we declare variables, we want their names to give us a hint about what kind of information they hold. This is where being descriptive comes in handy. Instead of naming your variable 'x' or 'temp,' consider names like 'total_students' or 'average_temperature.' This way, when you or someone else reads your code later on, the variable names act like signposts, guiding you through the story of your program. It's all about clarity and making your code more understandable, not just for Python but for yourself and others who might work on the code in the future.

So, when you're naming your variables in Python, think of it as crafting a story that Python can easily follow. Use clear, meaningful names that follow these rules, and Python will be your coding buddy, understanding every word of your programming tale! Let’s look at some example variables.

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car_color

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address@school!

“Let’s consider the variable name.

Is it legal?

Is it descriptive?”

Allow for discussion.

“Is it legal? Does it start with a letter or underscore? Yes! It starts with the letter 'a'.�

Followed by Letters, Digits, or Underscores? Absolutely! It has letters and an underscore but….�

No Spaces or Special Characters? Well, we've got special characters in there, breaking the third rule. And since we broke one rule, it’s not a legal variable name.�

Is it Descriptive? Yes, it is descriptive. The name 'address@school!' gives us a clear idea that this variable holds information about an address at school. However, despite its descriptiveness, it doesn't quite follow the rules we discussed. It's a good example of why we need to balance descriptiveness with adherence to naming rules.��What are some ways that we could change this variable to meet the requirements?

Let's aim for names that start with a letter, use letters, digits, or underscores, avoid spaces and special characters, and are clear and descriptive. Now, let's try another example together!"

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a1

“Let’s consider the variable name.

Is it legal?

Is it descriptive?”

Allow for discussion.

"Alright, everyone, let's analyze the variable name 'a1' together.

Does it Start with a Letter or Underscore? Absolutely! It starts with the letter 'a', following the first rule.�

Followed by Letters, Digits, or Underscores? Yes, indeed. After the 'a', we have the digit '1', and that's allowed. So, it follows the second rule.�

No Spaces or Special Characters? Perfect! No spaces or special characters. It adheres to the third rule as well.�

Is it Descriptive?

Well, here's where it gets interesting. While it follows all the naming rules, the name 'a1' isn't the most descriptive. It doesn't give us a clear idea of what information it holds. It's a bit like having a box labeled 'miscellaneous.' So, it's meeting the rules but could be more descriptive.

In our journey of naming variables, it's essential to strike a balance between following the rules and being descriptive. Nice job!

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Scavenger Hunt

TURN & TALK

INSTRUCTIONS

Discuss possible variable names for the scavenger hunt items

EXTENSIONS

Finished early? See if you notice any similarities in the types of data each variable might hold.

Item
Number of Chairs
Color of a backpack
Electronic Devices
Number of Windows

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number_of_pencils

8

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PyCharm

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“Just as we follow specific rules for naming our variables, we also have to use the right syntax for assigning values, especially when dealing with different data types. Some of you noticed that we had numbers for items from the scavenger hunt and some of you noticed we had groups of text that make words. These are considered different data types. We have different approaches for assigning values based on the datatypes.

When dealing with whole numbers (integers) or numbers with decimals (floats), you can assign them directly. No need for quotes; just type the number:

total_students = 30

average_temperature = 25.5

Strings, which are used for text or words, need a bit of special attention. To create a string variable, you use either single or double quotes:

course_title = 'Introduction to Python' uses a single quote while

teacher_name = "Mrs. Smith" uses double quotes. �

You can choose between single or double quotes based on your preference, just make sure to be consistent.

Finally, Python also has Booleans, which represent true or false values. No quotes needed:

is_raining = True

is_sunny = False”

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Right tool

for the

right job

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Create Variables

PARTNER ACTIVITY

INSTRUCTIONS

Declare and initialize the items from the Scavenger Hunt on the worksheet.
Open our inclass.py file and declare and initialize the variables.

EXTENSIONS

Print the variables to the console.
Add a text label before printing the value to the console.
Create a simple Madlib. Create a list of variables and use those variables, combined with text, to make a silly sentence or nursery rhyme.

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Variables are named storage locations that hold data.

Variables have rules for declaring them.

After a variable is initialized, it holds a value.

SUMMARY

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inclass.py

Let’s review what we coded! We've got a list of variables, each representing an item from our scavenger hunt. Notice how we're declaring and initializing these variables:

number_of_chairs = 32: Here, we're creating a variable named number_of_chairs and giving it an initial value of 32. It's like saying, 'Let's keep track of the number of chairs, and right now, we have 32.'

backpack_color = "red": We're creating a variable to hold the color of a backpack, and it's initialized with the string 'red.'

number_of_electronic_devices = 45: Does this follow our variable naming rules? YES!

number_of_windows = 3: Lastly, we're keeping track of the number of windows, initializing the variable number_of_windows with a value of 3.

Your variable names might not be exactly like mine and that’s ok as long as they meet the variable naming rules. Let’s look at the next component.

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inclass.py

Extension 1

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inclass.py

Extension 2

“Finally, in the 2nd extension, we added labels to print in the console. Let's break it down:

print("We have " + str(number_of_chairs) + " in our classroom."): Here, we're combining a string with the value stored in number_of_chairs using the + operator. The str() function is used to convert the integer to a string so it can be concatenated.

print("My backpack is " + backpack_color + "."): This line prints a string, followed by the value stored in backpack_color, which is a string. No need for str() here since we're already dealing with a string variable.

print("I found " + str(number_of_electronic_devices) + " in this classroom."): Similar to the first line, we're combining a string with the value stored in number_of_electronic_devices, converting it to a string using str().

print("It has " + str(number_of_windows) + " windows."): Finally, we're printing a string, followed by the value stored in number_of_windows, converted to a string with str().

So, in this extension, we've labeled our outputs to make them more informative. Also, remember to use str() when dealing with integer variables in a print statement. This way, we can successfully display the contents of our variables. Let's run it and see the enhanced output on the console!"

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madlib.py

Extension 3

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WRAP UP

Save the inclass.py file.
Complete the wrap-up question and self assessment.
Return laptops to charging cart.
Submit the worksheet.
Smile and celebrate your accomplishments! Nice work!

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