04 How to Create Variable and Data Types in Python (Video in Khmer)

Hello friend! 👋 Every program need to keep data. In Python, we use variable for this.

In this post, I show you variable and data types in Python. Easy and short. 🐍

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📦 What is Variable?

Variable is like a box with a name. You put data inside the box. Later you can use the data again.

name = "Dara"
age = 20

print(name)
print(age)

Output:

Dara
20

• = mean put value into variable. It is not "equal" like in math.
• Python find the type by itself. No need write int or str before.

🎥 Video: Use Variable in Python (Khmer)

✅ Variable Name Rule

• Can use letter, number and _
• Cannot start with number
• Cannot have space
• Cannot use Python keyword like if, for, class
• Big letter and small letter are different: Age ≠ age

user_name = "Sok"   # good
user2 = "Sophea"    # good
2user = "Bad"       # error
user name = "Bad"   # error

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🔢 Number Data Type

Python have 2 main number type:

Type	Example	Mean
int	10, -5, 0	Whole number
float	3.14, -0.5	Number with dot

apple = 5
price = 1.25

total = apple * price
print(total)

Output:

6.25

➕ Math Operator

a = 10
b = 3

print(a + b)   # 13  add
print(a - b)   # 7   minus
print(a * b)   # 30  multiply
print(a / b)   # 3.3333333333333335  divide
print(a // b)  # 3   divide, keep whole number only
print(a % b)   # 1   remainder
print(a ** b)  # 1000  power

🎥 Video: Using Numbers Data Type in Python (Khmer)

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🔤 String Data Type

String is text. Put it inside " " or ' '.

first = "Hello"
second = 'Python'

print(first + " " + second)

Output:

Hello Python

✅ Useful String Example

text = "python"

print(text.upper())     # PYTHON
print(text.capitalize())# Python
print(len(text))        # 6
print(text[0])          # p  (first letter)
print(text[-1])         # n  (last letter)
print(text[0:3])        # pyt  (slice)

🎥 Video: Using String Data Type in Python (Khmer)

✅ String Part 2: f-string and More

Use f-string to put variable inside text. Very easy!

name = "Dara"
age = 20

print(f"My name is {name}, I am {age} years old.")

Output:

My name is Dara, I am 20 years old.

More string trick:

text = "  Hello Python  "

print(text.strip())            # "Hello Python"  remove space
print(text.replace("Python", "World"))
print("Hello Python".split())  # ['Hello', 'Python']
print("py" in "python")        # True

🎥 Video: Using String Data Type in Python Part 2 (Khmer)

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🔍 Check Type with type()

print(type(10))       # <class 'int'>
print(type(3.14))     # <class 'float'>
print(type("Hello"))  # <class 'str'>

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❌ Common Error

Cannot add number and string directly:

age = 20
print("I am " + age)

Error:

TypeError: can only concatenate str (not "int") to str

Fix: use str() or f-string.

print("I am " + str(age))
print(f"I am {age}")

Input always give string:

num = input("Enter number: ")
print(num + 1)          # error
print(int(num) + 1)     # good

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💡 Tips

• Use clear name: student_name is better than x.
• Use snake_case for variable name in Python: total_price.
• Use f-string for print text with variable. Easy to read.
• Don't forget quote for string: "Hello" not Hello.
• Use type() when you not sure what type it is.
• Use int(), float(), str() to change type.
• Use # to write comment and note your code.

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❓ Any Question?

Tell us in comment below! 👇

#Python #Variable #DataTypes #String #Number #LearnPython

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