{"id":12812,"date":"2023-02-10T07:09:34","date_gmt":"2023-02-10T07:09:34","guid":{"rendered":"https:\/\/www.prepbytes.com\/blog\/?p=12812"},"modified":"2023-07-03T06:19:54","modified_gmt":"2023-07-03T06:19:54","slug":"how-to-use-def-function-in-python","status":"publish","type":"post","link":"https:\/\/prepbytes.com\/blog\/how-to-use-def-function-in-python\/","title":{"rendered":"How to Use Def Function in Python?"},"content":{"rendered":"

\"\"<\/p>\n

Python, renowned for its simplicity and versatility, offers a rich set of features that make it a popular programming language among beginners and experts alike. def in Python serves as the gateway to defining and utilizing functions.<\/p>\n

The "def" keyword, short for "define," is a crucial component of Python’s syntax that allows developers to create reusable blocks of code. By encapsulating a set of instructions within a named function, programmers can improve code organization, promote code reusability, and enhance the overall efficiency of their programs.<\/p>\n

What is Def in Python?<\/h2>\n

In Python, the "def" keyword is used to define a function. A function is a reusable block of code that performs a specific task or a set of instructions. It allows you to break down your code into smaller, manageable pieces, promoting code organization, reusability, and modularity.
\nThe "def" function declaration starts with the keyword "def," followed by the name of the function, parentheses (), and a colon (:). <\/p>\n

Working with Python Def<\/h2>\n

In order to write functions in python, we are aware of how to write a def keyword, and how it works in simple computing terms and what variation it can have, we will study this in this section.<\/p>\n

Syntax of user-defined function<\/h3>\n
def function_name(parameters):\n    \"\"\"Optional documentation string (docstring)\"\"\"\n    code to be executed\n    return [expression]<\/code><\/pre>\n
Components of a Function<\/h3>\n
A function comprises the parts as discussed below:- <\/p>\n
    \n
  1. def keyword<\/li>\n
  2. Function name<\/li>\n
  3. Function statements<\/li>\n
  4. Parameters<\/li>\n
  5. Return statement (optional)<\/li>\n<\/ol>\n
    1\ufe0f. Def Keyword<\/strong>
    \nIt is written at the start of the function indicating a user-defined function is being created to be put into use for calling in the later stages of the program.<\/p>\n
    2\ufe0f. Function Name<\/strong>
    \nIt is the name of the function. Advised to name the functions meaningful, accordingly with its purpose, in order to make the program more readable.<\/p>\n
    3\ufe0f. Function Parameters<\/strong>
    \nPassed arguments upon the calling of functions are set as parameters on defining a function using Python Def. The positioning of the parameter depends upon the position or keyword of the arguments.<\/p>\n
    Let us have a look a how positional and keyword arguments fare among each other.<\/p>\n
    Position Argument:<\/strong>
    \nThe parameters are executed in the order assigned to them at the time of calling the function. Such that an argument at the first position will be ordered first in the parameter.<\/p>\n
    def print_name(first_name, last_name):\n  print(\"First name:\", first_name)\n  print(\"Last name:\", last_name)\n\nprint_name(\"PrepBytes\", \"Learning\")<\/code><\/pre>\n
    Output:<\/strong><\/p>\n
    First name: PrepBytes\nLast name: Learning<\/code><\/pre>\n
    Keyword Argument:<\/strong>
    \nThe parameters are executed in the keyword assigned to them at the time of calling the function. Such that an argument at the first_name will be passed to the parameter named first_name<\/p>\n
    def print_name(first_name, last_name):\n  print(\"First name:\", first_name)\n  print(\"Last name:\", last_name)\n\nprint_name(first_name=\"PrepBytes\", last_name=\"Learning\")<\/code><\/pre>\n
    Output:<\/strong><\/p>\n
    First name: PrepBytes\nLast name: Learning<\/code><\/pre>\n
    4\ufe0f. Function Statements<\/strong>
    \nThese are the actual statements to be executed within the function. Function statements are indented two spaces or four spaces, as per the preference of the user.<\/p>\n
    def greeting(name):\n    print(\"Hello, \" + name)\n\ngreeting(\"John\")<\/code><\/pre>\n
    In the above code, Hello John will be printed as our function statement has a print function with name as the function parameter holding the name value.<\/p>\n
    5\ufe0f. Docstrings<\/strong>
    \nStrings that are kept as a commented code inside the function created for the sake of accessibility of the developer to know and store important documentation related to the function. It is another optional preference to keep docstrings inside the function. Accessed using  doc<\/strong>.<\/p>\n
    def exp(a, b):\n    \"\"\"Returns the power of a raised to the power b\"\"\"\n\n    return a**b\n\nprint(exp.__doc__)<\/code><\/pre>\n
    6\ufe0f. Return<\/strong>
    \nReturn is another optional but useful statement that returns the value back to the called function that requires an output generated from the set of statements generated inside the function.<\/p>\n
    In given example, we return the square of the number that is passed as an argument.<\/p>\n
    def sq(x):\n    return x * x\n\nresult = sq(5)\nprint(result)<\/code><\/pre>\n
    Output:<\/strong><\/p>\n
    25<\/code><\/pre>\n
    Among the discussed above, Python Def is the most used keyword in Python Programming Language.<\/p>\n
    Implementing Programs using Python Def<\/h2>\n
    With some solid knowledge of functional programming in python, let us hop on to see how python def can prove to be a handy tool in different scenarios of programming.<\/p>\n
    In the first of the two examples, we will be finding the multiples of a number up to ten.<\/p>\n\t\t\t\t\t\t