{"id":5686,"date":"2023-10-08T18:51:03","date_gmt":"2023-10-08T13:21:03","guid":{"rendered":"https:\/\/nolowiz.com\/?p=5686"},"modified":"2023-10-08T18:51:16","modified_gmt":"2023-10-08T13:21:16","slug":"partial-functions-in-python","status":"publish","type":"post","link":"https:\/\/nolowiz.com\/partial-functions-in-python\/","title":{"rendered":"Partial Functions in Python"},"content":{"rendered":"\n

In this tutorial, we will learn partial functions and their usage in Python.<\/p>\n\n\n\n

What is Partial function?<\/h2>\n\n\n\n

A partial function in programming is a function that is defined for only a subset of possible inputs. It allows you to specify a fixed number of arguments in advance, leaving some arguments to be provided later. This can be useful for creating reusable and flexible code. <\/p>\n\n\n\n

In Python, we can use the functools’ partial function<\/a> to implement the partial function.The functools is a module in Python’s standard library that provides higher-order functions and operations on callable objects.<\/p>\n\n\n\n

Example 1: <\/h3>\n\n\n\n

Let’s understand with an example, suppose we have a function to multiply two numbers.<\/p>\n\n\n

\ndef multiply(first_num, second_num):\n  '''Multiply two numbers'''\n  return first_num * second_num\n<\/pre><\/div>\n\n\n
We can convert the multiply function to calculate the double of a number using partial function.<\/p>\n\n\n
\nfrom functools import partial\n\ndouble = partial(multiply,second_num=2)\n<\/pre><\/div>\n\n\n
Here one argument to multiply function is fixed(2), the partial function double can accept one number. Now we can call the function double :<\/p>\n\n\n
\nprint(double(52))\n<\/pre><\/div>\n\n\n
Output<\/strong><\/p>\n\n\n\n
104<\/code><\/pre>\n\n\n\n
We can also add docstring<\/a> to the partial function using the __doc__ dunder function.<\/p>\n\n\n
\nfrom functools import partial\n\ndouble = partial(multiply,second_num=2)\ndouble.__doc__ = "Calcualte double of the number"\n<\/pre><\/div>\n\n\n
Example 2:<\/h3>\n\n\n\n
Suppose we have a function to calculate the power of a number.<\/p>\n\n\n
\ndef power(number,exponent):\n  return number ** exponent\n<\/pre><\/div>\n\n\n
We can define a square and cube partial functions as shown below :<\/p>\n\n\n
\nsquare = partial(power,exponent=2)\ncube = partial(power,exponent=3)\n<\/pre><\/div>\n\n\n
We can call cube partial function :<\/p>\n\n\n
\nprint(cube(5))\n<\/pre><\/div>\n\n\n
Output<\/strong><\/p>\n\n\n\n
125<\/code><\/pre>\n\n\n\n
When to use Partial functions<\/h2>\n\n\n\n
Partial functions are usable in the following contexts :<\/p>\n\n\n\n