{"id":183004,"date":"2024-03-13T10:24:00","date_gmt":"2024-03-13T09:24:00","guid":{"rendered":"https:\/\/liora.io\/en\/?p=183004"},"modified":"2026-02-06T08:24:48","modified_gmt":"2026-02-06T07:24:48","slug":"python-lambda-functions-principles-and-benefits","status":"publish","type":"post","link":"https:\/\/liora.io\/en\/python-lambda-functions-principles-and-benefits","title":{"rendered":"Python Lambda functions: principles and benefits"},"content":{"rendered":"\n.elementor-heading-title{padding:0;margin:0;line-height:1}.elementor-widget-heading .elementor-heading-title[class*=elementor-size-]>a{color:inherit;font-size:inherit;line-height:inherit}.elementor-widget-heading .elementor-heading-title.elementor-size-small{font-size:15px}.elementor-widget-heading .elementor-heading-title.elementor-size-medium{font-size:19px}.elementor-widget-heading .elementor-heading-title.elementor-size-large{font-size:29px}.elementor-widget-heading .elementor-heading-title.elementor-size-xl{font-size:39px}.elementor-widget-heading .elementor-heading-title.elementor-size-xxl{font-size:59px}

For small operations, regular functions in Python can take up a lot of space, making syntax difficult to read. This is why Lambda functions are so useful in Python. <\/strong><\/p>\t\t\n\t\t

How do you use them and why? Find out in this article.<\/p>

 <\/p>

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Lambda functions in Python, anonymous functions<\/h3>\t\t\n\t\t

In Python, a Lambda function is an anonymous function. In other words, a function declared without a name. Its syntax is as follows:<\/p>

Lambda arguments: expression<\/pre>
As this is a single-line syntax<\/b>, the function is much more readable. There’s no need to search for the argument on another line. Although the syntax is different from regular functions declared with the def keyword, they behave in the same way. It’s just more concise. <\/b><\/p>
Aside from its lack of a name and its conciseness, the Lambda functions in python are characterized by the fact that they contain only one expression<\/b>. On the other hand, they can have several arguments. <\/p>\t\t\n\t\t\t
4 exemples de fonctions Lambda<\/h3>\t\t\n\t\t
To help you better understand the difference between Python’s Lambda functions and regular functions, here are a few examples:<\/p>\t\t\n\t\t\t
Lambda and sum functions<\/h4>\t\t\n\t\t
If you want to calculate the sum of two values, your code can be one of these two formulas.<\/p>\t\t\n\t\t\t\n.tg  {border-collapse:collapse;border-spacing:0;}\n.tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px;\n  overflow:hidden;padding:10px 5px;word-break:normal;}\n.tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px;\n  font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;}\n.tg .tg-7vx0{font-family:Tahoma, Geneva, sans-serif !important;font-size:16px;font-weight:bold;text-align:center;vertical-align:top}\n.tg .tg-9kad{font-family:Tahoma, Geneva, sans-serif !important;font-size:16px;text-align:left;vertical-align:top}\n\n\n\n\n\n<\/colgroup>\n\n  \n    \n  \n    
Regular Function in Python<\/th>\n    Lambda Function in Python<\/th>\n  <\/tr>\n<\/thead>\n
1 def sum_classic( a , b ):
2   return a + b<\/td>\n    		sum_Lambda = Lambda a,b : a+b<\/td>\n  <\/tr>\n<\/tbody>\n<\/table>\n\t\t\t\n
Learn to use lambda functions<\/a><\/div><\/div>\n\n\t\t\t
Lambda function and map  <\/h4>\t\t\n\t\t
With the map function, you can double each element of a list.<\/p>
Here are the differences between the Lambda function and the regular function.<\/p>\t\t\n\t\t\t\n.tg  {border-collapse:collapse;border-spacing:0;}\n.tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px;\n  overflow:hidden;padding:10px 5px;word-break:normal;}\n.tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px;\n  font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;}\n.tg .tg-7vx0{font-family:Tahoma, Geneva, sans-serif !important;font-size:16px;font-weight:bold;text-align:center;vertical-align:top}\n.tg .tg-n3o3{background-color:#efefef;font-family:Tahoma, Geneva, sans-serif !important;font-size:16px;text-align:left;\n  vertical-align:top}\n\n\n\n\n\n<\/colgroup>\n\n  \n    \n  \n    
Regular Function in Python<\/th>\n    Lambda Function in Python<\/th>\n  <\/tr>\n<\/thead>\n
1 def doubler(x):
2   return x * 2
3 list = [1, 2, 3, 4, 5]
4 result_def = list(map(doubler, list))
5 print(result_def)  <\/td>\n    		1 list = [1, 2, 3, 4, 5]
2 result_lambda = list(map(lambda x: x * 2, list))
3 print(result_lambda)  <\/td>\n  <\/tr>\n<\/tbody>\n<\/table>\n\t\t
This will display [2, 4, 6, 8, 10].<\/p>\t\t\n\t\t\t
Lambda and filter functions<\/h4>\t\t\n\t\t
With the map function, you can filter certain elements. In this example, the aim is to filter out even numbers from a list.<\/p>
Here are the differences between the Lambda function and the regular function.<\/p>\t\t\n\t\t\t\n.tg  {border-collapse:collapse;border-spacing:0;}\n.tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px;\n  overflow:hidden;padding:10px 5px;word-break:normal;}\n.tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px;\n  font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;}\n.tg .tg-7vx0{font-family:Tahoma, Geneva, sans-serif !important;font-size:16px;font-weight:bold;text-align:center;vertical-align:top}\n.tg .tg-n3o3{background-color:#efefef;font-family:Tahoma, Geneva, sans-serif !important;font-size:16px;text-align:left;\n  vertical-align:top}\n\n\n\n\n\n<\/colgroup>\n\n  \n    \n  \n    
Regular Function in Python<\/th>\n    Lambda Function in Python<\/th>\n  <\/tr>\n<\/thead>\n
1 def is_even(x):
2 return x % 2 == 0
3 list = [1, 2, 3, 4, 5, 6, 7, 8, 9]
4 result_def = list(filter(is_even, list))
5 print(result_def)<\/td>\n    		1 list = [1, 2, 3, 4, 5, 6, 7, 8, 9]
2 result_lambda = list(filter(lambda x: x % 2 == 0, list))
3 print(result_lambda)  <\/td>\n  <\/tr>\n<\/tbody>\n<\/table>\n\t\t
In both cases, it will display [2, 4, 6, 8].<\/p>\t\t\n\t\t\t\n
Mastering lambda functions<\/a><\/div><\/div>\n\n\t\t\t
Lambda and sorted functions<\/h4>\t\t\n\t\t
With the map function, you can sort a list. In this example, a list of tuples will be sorted according to the second element.<\/p>
Here’s the code to type for both types of function:<\/p>\t\t\n\t\t\t\n.tg  {border-collapse:collapse;border-spacing:0;}\n.tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px;\n  overflow:hidden;padding:10px 5px;word-break:normal;}\n.tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px;\n  font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;}\n.tg .tg-7vx0{font-family:Tahoma, Geneva, sans-serif !important;font-size:16px;font-weight:bold;text-align:center;vertical-align:top}\n.tg .tg-n3o3{background-color:#efefef;font-family:Tahoma, Geneva, sans-serif !important;font-size:16px;text-align:left;\n  vertical-align:top}\n\n\n\n\n\n<\/colgroup>\n\n  \n    \n  \n    
Regular Function in Python<\/th>\n    Lambda Function in Python<\/th>\n  <\/tr>\n<\/thead>\n
1 def key_sort(tuple):
2   return tuple[1]
3 tuples = [(1, 5), (3, 2), (8, 10), (4, 7)]
4 result_def = sorted(tuples, key=key_sort)
5 print(result_def) <\/td>\n    		1 tuples = [(1, 5), (3, 2), (8, 10), (4, 7)] 
2 result_lambda = sorted(tuples, key=lambda x: x[1])
3 print(result_lambda) <\/td>\n  <\/tr>\n<\/tbody>\n<\/table>\n\t\t
This will display [(3, 2), (1, 5), (4, 7), (8, 10)].<\/p>
Apart from these examples, Lambda functions on Python are best used with simple functions for a one-off operation, such as apply(), sorted(), applymap() or reduce().<\/p>\t\t\n\t\t\t
Lambda function use cases in Python<\/h3>\t\t\n\t\t
The Lambda function in Python can be used in the following situations:<\/p>