Function in Python is reusable code that performs a specific task.
- It divides programs into smaller parts, making the code easier to read and understand.
- Functions can accept inputs called parameters or arguments.
- A function is a set of instructions that gets executed whenever it is called.
- Functions can return a value using the return keyword. If no return keyword is specified, the function implicitly returns None.
- Functions make programs more organized, readable, and maintainable
- To call a function use the function name followed by its parenthsis.
Functions are of three types.
- Built-in
- User-defined
- Lambda
- These are predefined functions already available in Python.
- They do not require importing any additional libraries or modules.
- Built-in functions perform common tasks like mathematical operations and type conversions.
- Examples: print(), int(), len(), etc.
User-defined Functions in Python
- User-defined functions are functions created by the user to perform specific tasks as per their requirements.
- They are defined using the def keyword.
- A function can return a value using the return keyword.
- User-defined functions support complex and logical code.
- Functions are called by their name, followed by parentheses.
- They can be reused, making programs more organized and manageable.
- The number of lines in a user-defined function depends on how simple or complex the task is.
- A lambda function is an anonymous function.
- It is defined using the lambda keyword.
- Used for short, single-line expressions.
- It can only have one expression.
- Lambda functions can take multiple arguments.
- No return keyword is needed.
- Allows you to pass functions as arguments.
- Lambda functions are useful when you need a function for a short period or a single line of code
Why Do We Use Functions ???
- Reusability: You can use the same code multiple times without rewriting it.
- Modularity: Functions break programs into smaller, easier-to-handle parts.
- Readability: They make the code cleaner and easier to understand.
- Debugging: Errors are easier to find and fix within a function.
- Efficiency: Functions save time by reducing repeated code.
- Flexibility: You can use inputs (parameters) to make functions work for different tasks.
- Maintainability: Changes can be made in one place instead of updating code everywhere.
