2. Variables in Python

1. Variable

Variables are an important concept used to store and manage data in programming. A variable is a named memory space that is used to store or reference a value.

 

2. Data Types of Variables

• Dynamic typing: Automatically infer the type of a variable when assigning a value without having to declare it.
• Pros: Reduces the burden on programmers and can make code more concise.
• Cons: Values of the wrong type can be assigned to variables.

Basic Data Types: 

• Integer Type (int): Represents integer values (e.g., 1, 2, 3)
• Floating-Point Type (float): Represents real numbers (e.g., 3.14, 1.234)
• String Type (str): Represents characters or strings (e.g., "Hello", "Python")
• Boolean Type (bool): Represents True or False values

Collection Data Types: 

• List (list): A data structure that stores multiple values sequentially (e.g., [1, 2, 3], ["apple", "banana"])
• Tuple (tuple): Similar to a list but is immutable (e.g., (1, 2, 3), ("Kim Apple", 20))
• Dictionary (dict): A data structure that stores key-value pairs (e.g., {"name": "Kim Apple", "age": 20})
• Set (set): A data structure that stores unique values (e.g., {1, 2, 3})

 

3. Variable Deletion

 

del statement :

• It is used to delete variables.
• It removes the specified variable and releases the corresponding memory space.
• Once a variable is deleted, you can no longer access it using that name.

변수 존재하기 때문에 출력

변수 삭제 후 출력 > 에러 발생

 

4. Additional Information

• Variable Naming Rules:
  • Must start with a letter, number, or underscore (_).
  • Cannot contain special characters.
  • Case-sensitive.
  • Cannot use reserved keywords.
• Variable Declaration:
  • Variable declaration happens automatically when you assign a value to it.