--- title: 2.14 Basic Data Types description: "A **data type** defines the kind of value that a variable can store and the operations that can be performed on that value. Python provides several built-in data types. The most commonly used basic data types are: - `int` (Integer)…" url: "https://edcret.in/docs/python-programming/basic-refreshers-python/2-14-basic-data-types/" updated: "2026-07-29" category: Python Programming / Basic Refreshers --- # 2.14 Basic Data Types A **data type** defines the kind of value that a variable can store and the operations that can be performed on that value. Python provides several built-in data types. The most commonly used basic data types are: - `int` (Integer) - `float` (Floating-Point Number) - `complex` (Complex Number) - `bool` (Boolean) - `str` (String) Every value in Python belongs to one of these data types. --- ## Example 1: Integer (`int`) **main.py** ``` age = 25 print(age) print(type(age)) ``` ### Output ``` 25 ``` ### Explanation - `25` is an integer value. - Integers are whole numbers without a decimal point. - The `type()` function confirms that the value belongs to the `int` data type. --- ## Example 2: Floating-Point Number (`float`) **main.py** ``` price = 99.95 print(price) print(type(price)) ``` ### Output ``` 99.95 ``` ### Explanation - `99.95` contains a decimal point. - Therefore, Python stores it as a floating-point number. - Floating-point numbers are represented by the `float` data type. --- ## Example 3: Complex Number (`complex`) **main.py** ``` number = 3 + 4j print(number) print(type(number)) ``` ### Output ``` (3+4j) ``` ### Explanation - A complex number contains a real part and an imaginary part. - The imaginary part is represented using the letter `j`. - Python provides built-in support for complex numbers through the `complex` data type. --- ## Example 4: Boolean (`bool`) **main.py** ``` result1 = True result2 = False print(result1) print(result2) print(type(result1)) ``` ### Output ``` True False ``` ### Explanation - Boolean values can only be `True` or `False`. - They are commonly used in decision-making and comparisons. - The data type of Boolean values is `bool`. --- ## Example 5: String (`str`) **main.py** ``` language = "Python" print(language) print(type(language)) ``` ### Output ``` Python ``` ### Explanation - A string is a sequence of characters enclosed in quotation marks. - Strings are represented by the `str` data type. - Strings can contain letters, numbers, symbols, and spaces. --- ## Example 6: Multiple Data Types **main.py** ``` age = 25 height = 5.9 name = "Alice" is_student = True print(type(age)) print(type(height)) print(type(name)) print(type(is_student)) ``` ### Output ``` ``` ### Explanation - Python variables can store different kinds of data. - Each variable has its own data type. - The `type()` function displays the type of every variable. --- ## Example 7: Scientific Notation **main.py** ``` distance = 3.5e6 print(distance) print(type(distance)) ``` ### Output ``` 3500000.0 ``` ### Explanation - Scientific notation uses `e` or `E`. - `3.5e6` means `3.5 × 10⁶`. - Scientific notation values are stored as floating-point numbers. --- ## Example 8: Type Conversion Between Data Types **main.py** ``` number = 25 decimal = float(number) print(decimal) print(type(decimal)) ``` ### Output ``` 25.0 ``` ### Explanation - `number` is an integer. - `float()` converts it into a floating-point number. - The converted value has the `float` data type. --- ## Example 9: Using Different Data Types Together **main.py** ``` name = "Alice" age = 22 height = 5.4 print(name, age, height) ``` ### Output ``` Alice 22 5.4 ``` ### Explanation - Python allows different data types to be used together. - The `print()` function can display values of different types in a single statement. - By default, `print()` separates the values with spaces. --- ## Example 10: Checking the Data Type **main.py** ``` value = False print(type(value)) ``` ### Output ``` ``` ### Explanation - The variable `value` stores the Boolean value `False`. - The `type()` function identifies its data type. - The returned type is `bool`. --- # Common Mistakes ### 1. Assuming Numbers with Decimal Points are Integers **Incorrect Assumption** ``` number = 10.0 ``` ### Incorrect Expectation ``` ``` ### Actual Output ``` ``` **Reason** Any numeric value containing a decimal point is a floating-point number. --- ### 2. Forgetting Quotes Around Strings **Incorrect** ``` name = Python ``` ### Output ``` NameError: name 'Python' is not defined ``` **Reason** Text values must be enclosed in quotation marks. **Correct** ``` name = "Python" ``` --- ### 3. Using `true` and `false` Instead of `True` and `False` **Incorrect** ``` status = true ``` ### Output ``` NameError: name 'true' is not defined ``` **Reason** Python Boolean values are written as `True` and `False` with uppercase first letters. **Correct** ``` status = True ``` --- ### 4. Confusing Strings with Numbers **Incorrect** ``` age = "25" print(age + 5) ``` ### Output ``` TypeError: can only concatenate str (not "int") to str ``` **Reason** `"25"` is a string, not an integer. **Correct** ``` age = int("25") print(age + 5) ``` --- # Best Practices - Choose the appropriate data type for the information being stored. - Use `type()` while learning to verify data types. - Keep numeric and string data separate unless conversion is required. - Use meaningful variable names that indicate the type of data being stored. - Convert values explicitly when needed using functions such as `int()`, `float()`, and `str()`. --- # Key Points to Remember - A data type specifies the kind of value stored by a variable. - Python's common basic data types include `int`, `float`, `complex`, `bool`, and `str`. - Integers represent whole numbers. - Floating-point numbers represent numbers with decimal points. - Complex numbers use the `j` suffix for the imaginary part. - Boolean values are `True` and `False`. - Strings are sequences of characters enclosed in quotation marks. - The `type()` function returns the data type of a value or variable.