{"id":51,"date":"2024-01-24T14:20:35","date_gmt":"2024-01-24T14:20:35","guid":{"rendered":"https:\/\/learnpython.elegantwallp.com\/?p=51"},"modified":"2024-01-24T14:20:36","modified_gmt":"2024-01-24T14:20:36","slug":"python-default-parameters","status":"publish","type":"post","link":"https:\/\/learnpython.elegantwallp.com\/2024\/01\/24\/python-default-parameters\/","title":{"rendered":"Python Default Parameters"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you\u2019ll learn about the Python default parameters to simplify function calls.<\/p>\n\n\n\n

Introduction to Python default parameters<\/h2>\n\n\n\n

When you\u00a0define a function, you can specify a default value for each parameter.<\/p>\n\n\n\n

To specify default values for parameters, you use the following syntax:<\/p>\n\n\n\n

def function_name(param1, param2=value2, param3=value3, ...):<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
In this syntax, you specify default values (value2<\/code>, value3<\/code>, \u2026) for each parameter using the assignment operator (=)<\/code>.<\/p>\n\n\n\n
When you call a function and pass an argument to the parameter that has a default value, the function will use that argument instead of the default value.<\/p>\n\n\n\n
However, if you don\u2019t pass the argument, the function will use the default value.<\/p>\n\n\n\n
To use default parameters, you need to place parameters with the default values after other parameters. Otherwise, you\u2019ll get a syntax error.<\/p>\n\n\n\n
For example, you cannot do something like this:<\/p>\n\n\n\n
def function_name(param1=value1, param2, param3):<\/code><\/code><\/pre>\n\n\n\n
This causes a syntax error.<\/p>\n\n\n\n
Python default parameters example<\/h2>\n\n\n\n
The following example defines the\u00a0greet()<\/code>\u00a0function that returns a greeting message:<\/p>\n\n\n\n
def greet(name, message='Hi'): return f\"{message} {name}\"<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
The greet()<\/code> function has two parameters: name<\/code> and message<\/code>. And the message<\/code> parameter has a default value of 'Hi'<\/code>.<\/p>\n\n\n\n
The following calls the\u00a0greet()<\/code>\u00a0function and passes the two arguments:<\/p>\n\n\n\n
def greet(name, message='Hi'): return f\"{message} {name}\" greeting = greet('John', 'Hello') print(greeting)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Output:<\/p>\n\n\n\n
Hello John<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Since we pass the second argument to the greet()<\/code> function, the function uses the argument instead of the default value.<\/p>\n\n\n\n
The following example calls the\u00a0greet()<\/code>\u00a0function without passing the second argument:<\/p>\n\n\n\n
def greet(name, message='Hi'): return f\"{message} {name}\" greeting = greet('John') print(greeting)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Output:<\/p>\n\n\n\n
Hi John<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
In this case, the greet()<\/code> function uses the default value of the message<\/code> parameter.<\/p>\n\n\n\n
Multiple default parameters<\/h2>\n\n\n\n
The following redefines the\u00a0greet()<\/code>\u00a0function with the two parameters that have default values:<\/p>\n\n\n\n
def greet(name='there', message='Hi'): return f\"{message} {name}\"<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
In this example, you can call the\u00a0greet()<\/code>\u00a0function without passing any parameters:<\/p>\n\n\n\n
def greet(name='there', message='Hi'): return f\"{message} {name}\" greeting = greet() print(greeting)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Output:<\/p>\n\n\n\n
Hi there<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Suppose that you want the\u00a0greet()<\/code>\u00a0function to return a greeting like\u00a0Hello there<\/code>. You may come up with the following function call:<\/p>\n\n\n\n
def greet(name='there', message='Hi'): return f\"{message} {name}\" greeting = greet('Hello') print(greeting)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Unfortuntely, it returns an unexpected value:<\/p>\n\n\n\n
Hi Hello<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Because when you pass the 'Hello'<\/code> argument, the greet()<\/code> function treats it as the first argument, not the second one.<\/p>\n\n\n\n
To resolve this, you need to call the\u00a0greet()<\/code>\u00a0function using\u00a0keyword arguments\u00a0like this:<\/p>\n\n\n\n
def greet(name='there', message='Hi'): return f\"{message} {name}\" greeting = greet(message='Hello') print(greeting)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Output:<\/p>\n\n\n\n
Hello there<\/code><\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
Summary: in this tutorial, you\u2019ll learn about the Python default parameters to simplify function calls. Introduction to Python default parameters When you\u00a0define a function, you can specify a default value for each parameter. To specify default values for parameters, you use the following syntax: In this syntax, you specify default values (value2, value3, \u2026) for each […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[18],"tags":[],"class_list":["post-51","post","type-post","status-publish","format-standard","hentry","category-4-functions"],"_links":{"self":[{"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/posts\/51","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/comments?post=51"}],"version-history":[{"count":1,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/posts\/51\/revisions"}],"predecessor-version":[{"id":52,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/posts\/51\/revisions\/52"}],"wp:attachment":[{"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/media?parent=51"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/categories?post=51"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/tags?post=51"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}