Introduction to Data Type and Variables

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A variable is a named container that stores a value in computer memory. Its data type is not fixed and changes depending on the value it holds. A variable is declared automatically when a value is ass…

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An identifier is a name given to programming elements such as a variable, function, class, module, or any other object. It must follow naming rules such as starting with a letter or underscore and avo…

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An identifier must begin with a letter or underscore, use only letters, digits, and underscore, contain no blank spaces, not be a keyword, be case sensitive, and can be of any size.

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All four are valid identifiers because they follow the rules for naming in Python.

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All three are invalid identifiers. rate of interest contains a blank space, 1student starts with a digit, and @age contains a special symbol not allowed in identifiers.

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A keyword is a reserved word with a special meaning to the Python interpreter. Keywords cannot be used as variable names. Python has 33 keywords, and all are lowercase except False, None, and True.

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Keywords already have a special meaning in Python, so they are reserved for the language itself. Using them as variable names would cause confusion and errors.

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A variable is a user-defined name used to store a value, while a keyword is a reserved word with a fixed meaning in Python. Variables are not reserved, but keywords are.