Lambda (programming)

In programming languages such as Lisp, C#, Ruby and Python, lambda is an operator used to denote anonymous functions or closures, following the usage of lambda calculus.

Examples

Python

An example of this use of lambda in the Python language is this section of computer code that sorts a list alphabetically by the last character of each entry:

>>> stuff = ['woman', 'man', 'horse', 'boat', 'plane', 'dog']
>>> sorted(stuff, key=lambda word: word[-1])
['horse', 'plane', 'dog', 'woman', 'man', 'boat']

C Sharp (programming language)

In C#, lambda expressions are often used with LINQ:

var allWikipediaPages = GetAllWikipediaPages();
var lambdaWikipediaPage = allWikipediaPages.First(wp => wp.Title == "Lambda (programming)");