Intro Python- Variables

Summary

This educational video script introduces the concept of variables in programming, focusing on Python. It explains that variables store information like text or numbers which can be used later in a program. The script covers variable attributes: name, type, and value, using 'greeting' and 'my number' as examples. It differentiates between 'string' (text) and 'int' (integer) types, and briefly mentions 'float' (decimal numbers). The video also demonstrates how to create and update variables using assignment statements and how to print a variable's type using the 'type' function.

Takeaways

• 📚 Variables are a fundamental aspect of programming languages used to store information.
• 🔑 A variable has three characteristics: a name, a type, and a value.
• 🌐 The variable 'greeting' is used in the script to demonstrate a variable with the value 'hello, world'.
• 🔢 The variable 'my number' is shown with the value 50, illustrating how variables can store numerical data.
• 📝 The type 'str' stands for string, which is used for variables that contain text or a sequence of characters.
• 🔢 The type 'int' stands for integer, used for variables that contain whole numbers without decimal points.
• 💧 Strings can also be surrounded by single quotes in Python, but the course will use double quotes.
• 🔄 The 'float' type, which allows for decimal numbers, is mentioned as a future topic.
• 📝 Assignment statements in Python are used to create or update variables with an equal sign.
• 🔍 The 'type' function in Python can be used to print the type of a variable, such as 'str' or 'int'.

Q & A

What is a variable in programming?

A variable is something that stores information in a program so that it can be used later. This information can be text or numbers.

What are the three characteristics of a variable?

The three characteristics of a variable are its name, type, and value.

What is the name of the variable in the example program that stores the text 'hello world'?

The name of the variable is 'greeting'.

What type is associated with the variable 'greeting' in the script?

The type of the variable 'greeting' is 'str', which stands for string.

What does the type 'int' stand for and what kind of values can it hold?

The type 'int' stands for integer and it can hold whole numbers, which can be positive, negative, or zero.

How can you print the value of a variable in Python?

You can print the value of a variable in Python by using the 'print' function followed by the variable name without quotes.

What is the purpose of the 'type' function in Python?

The 'type' function in Python is used to determine and print the data type of a variable.

What is a floating-point number and what is its Python type?

A floating-point number is a number with a decimal component. In Python, this type of number is represented by the 'float' type.

How do you create or update a variable in Python?

You can create or update a variable in Python using an assignment statement, which consists of the variable name on the left, an equal sign in the middle, and the value on the right.

Can you use single quotes to define a string in Python as mentioned in the script?

While strings can be surrounded by single quotes in Python, the script specifies that double quotes will be used in this course.

What is the difference between 'int' and 'float' types in Python?

The 'int' type represents integers without a decimal component, whereas 'float' represents numbers that can have a decimal component.

Outlines

00:00

💻 Introduction to Variables in Programming

This paragraph introduces the concept of variables in programming, which are fundamental to almost every programming language. The script explains variables through examples in a program, such as 'greeting' with the value 'hello, world' and 'my number' with the value 50. It defines a variable as something that stores information in a program for later use, which can be text or numbers. The paragraph further breaks down a variable into three characteristics: name, type, and value. For 'greeting', the type is 'str' (string), which contains text, and for 'my number', the type is 'int' (integer), which contains whole numbers. The paragraph also mentions the 'float' type for variables that can hold decimal numbers. It concludes by explaining how to create or update variables in Python using assignment statements with an equal sign.

Keywords

💡Variables

Variables are fundamental components in programming that store information to be used later in a program. They are essential for manipulating data and controlling program flow. In the video, variables such as 'greeting' and 'my number' are introduced to demonstrate how they hold values like 'hello, world' and the number 50, respectively. Variables are a core concept in programming, allowing for dynamic and interactive software behavior.

💡Name

The name of a variable is the identifier used to reference the stored data within a program. It is a crucial part of declaring a variable as it provides a way to access and manipulate the variable's value. In the script, 'greeting' and 'my number' are examples of variable names, which are used to store and later print the values 'hello, world' and 50.

💡Type

The type of a variable refers to the kind of data it can hold. It determines the operations that can be performed on the data and how the data is stored in memory. The video explains two types: 'str' for strings, which are sequences of characters, and 'int' for integers, which are whole numbers. Understanding variable types is crucial for writing programs that handle data correctly.

💡Value

The value is the actual data stored in a variable. It can be changed and retrieved as needed during program execution. In the context of the video, the variable 'greeting' holds the value 'hello, world', and 'my number' holds the value 50. Values give variables their utility by providing the specific data that programs operate on.

💡String (str)

A string is a sequence of characters that can include letters, numbers, punctuation, and spaces. In programming, strings are typically used to handle text data. The video mentions that 'hello, world' and 'abc123' are examples of string values. Understanding strings is important for tasks like processing text, user input, and generating output.

💡Integer (int)

An integer is a whole number, which can be positive, negative, or zero, and does not include a decimal point. In the video, 'my number' is an integer variable with the value 50. Integers are fundamental in programming for performing arithmetic operations and representing discrete quantities.

💡Assignment Statement

An assignment statement is used to create a new variable or update an existing one by assigning a value to it. In the video, this is demonstrated with a single equal sign '=' used to assign values to variables. Assignment statements are a basic operation in programming, allowing for the dynamic setting of variable values.

💡Type Function

The type function is used to determine and return the data type of a variable. In the video, it is used to print the type of the 'greeting' variable, which outputs '<class 'str'>'. This function is useful for debugging and ensuring that variables are used correctly according to their declared types.

💡Floating-Point Number (float)

A floating-point number, or float, is a type of variable that can store numbers with decimal points. This includes positive or negative numbers like 3.2, 0.0, or 4.56. The video mentions floats as a type that will be covered in future lessons, indicating their importance in handling real numbers and performing calculations that require precision beyond whole numbers.

💡Print

The print function is a common operation in programming used to output data to the console or screen. In the video, it is used to display the values of variables like 'greeting' and 'my number'. Understanding how to use print is fundamental for displaying results and debugging in programming.

Highlights

Introduction to variables, a fundamental aspect of programming languages.

Explaining a program with a variable named 'greeting' that holds the value 'hello, world'.

Demonstration of printing a variable's value versus its type.

Definition of a variable as something that stores information to be used later in a program.

Variables have three characteristics: a name, a type, and a value.

Example of a variable 'greeting' with a name, type 'str', and value 'hello world'.

Explanation of the 'str' type for variables containing text or sequences of characters.

Clarification that strings can be surrounded by single quotes in Python, but double quotes will be used in the course.

Introduction to the 'int' type for variables containing whole numbers without decimals.

Examples of integers: positive, negative, and zero.

Introduction to the 'float' type for variables containing numbers with decimal components.

Explanation that the decimal component in floats can be zero, making 0.0 equal to the integer 0.

How to create or update a variable in Python using an assignment statement.

Structure of an assignment statement with variable name, equal sign, and value.

Using the 'type' function to print a variable's type, demonstrated with 'greeting'.

Using the 'type' function to confirm 'my number' variable's type as 'int'.

Anticipation of future lessons covering more advanced uses of variables.

Transcripts

alright welcome back in this video

you'll learn about something that is a

fundamental aspect of just about every

programming language variables let's

dive in and look at a program that has a

variable in it in a minute we'll take

some time to go over exactly what a

variable is and what it does the

variable in this program is called

greeting it has a value which is hello

world this means that printing greeting

is basically the same as printing hello

world

here's another program with a variable

the variable is called my number and its

value with the number 50 ok so what is a

variable a variable is something that

stores information in a program so that

it can be used later that information

can be something like hello world or the

number 50 more specifically a variable

has three things a name a type and a

value so let's look at the two variables

that we just saw and spell out each of

these three characteristics in the case

of variable greeting the name of the

variable is greeting the type of the

variable is ster which I'll explain in a

second and the value is hello world in

quotes

note that when you print the variable

greeting you don't put quotes around it

then we saw a variable whose name was my

number whose type was int which I'll

also explain in a second and whose value

is 50 okay so what do these types mean

stur is short for string a variable

whose type is ster contains text or a

sequence of zero or more characters and

these characters can be letters numbers

punctuation spaces whatever you can type

on your keyboard so hello world is an

example abc123 is an example or a string

can actually have zero characters okay

quick digression strings can also be

surrounded by single quotes in Python

however in this course we will use

double quotes now let's look at the type

int int is short for integer and a

variable whose type is int contains a

number and that number can be positive

negative or zero however it cannot have

a decimal component so negative 50 0 and

5 are all examples of integers another

type that we haven't seen yet but we

will in future lessons is float float is

short for floating-point number and this

is basically like an integer except it

does have a decimal component so

negative three point two zero point zero

or four point five six five two are all

examples of floats

note that the

Cemil component can be zero so zero

point zero is in fact equal to the

integers zero you can create a new

variable or update an existing variable

in python using what's called an

assignment statement this statement has

three parts on the left you have the

name of the variable on the right you

have the value that you want to give to

that variable and in the middle you just

have a single equal sign okay check out

this example program in the upper right

unlike the program that we saw a few

slides ago this program prints the type

of the variable greeting rather than the

value you can do this using the type

function the output is class stir in

triangle brackets and this might look a

little weird but the important part is

the part inside the single quotes stir

which is in fact the type of the

variable greeting now we can see the

type function being used on the variable

my number and sure enough the type is

int so that's the basics of variables in

Python in future videos you'll learn how

to do more interesting things with a

variable than just print its value or

its type