Include lambda shorthand notation in "Lambda Expressions: The fun Keyword" page (#43675)

* Mention the alternate notation of lambda expression in Syntax

* Modify lambda usage examples to show both notations

* Emphasize on the snippets being equivalent

Co-authored-by: Tomas Grosup <[email protected]>

* Update lambda-expressions-the-fun-keyword.md

Co-authored-by: Genevieve Warren <[email protected]>

* Update lambda-expressions-the-fun-keyword.md

Co-authored-by: Genevieve Warren <[email protected]>

* Update lambda-expressions-the-fun-keyword.md

Co-authored-by: Genevieve Warren <[email protected]>

* Update lambda-expressions-the-fun-keyword.md

Co-authored-by: Genevieve Warren <[email protected]>

* Update docs/fsharp/language-reference/functions/lambda-expressions-the-fun-keyword.md

---------

Co-authored-by: Tomas Grosup <[email protected]>
Co-authored-by: Vlad Zarytovskii <[email protected]>
Co-authored-by: Genevieve Warren <[email protected]>
Co-authored-by: Bill Wagner <[email protected]>

Author: 5 people

docs/fsharp/language-reference/functions/lambda-expressions-the-fun-keyword.md

@@ -13,6 +13,19 @@ The `fun` keyword is used to define a lambda expression, that is, an anonymous f
 fun parameter-list -> expression
 ```
 
+Or using the `_.Property` shorthand notation:
+
+```fsharp
+_.
+```
+
+`fun`, *parameter-list*, and lambda arrow (`->`) are omitted, and the `_.` is a part of *expression* where `_` replaces the parameter symbol.
+
+The following snippets are equivalent:
+
+`(fun x -> x.Property)`
+`_.Property`
+
 ## Remarks
 
 The *parameter-list* typically consists of names and, optionally, types of parameters. More generally, the *parameter-list* can be composed of any F# patterns. For a full list of possible patterns, see [Pattern Matching](../pattern-matching.md). Lists of valid parameters include the following examples.
@@ -41,10 +54,12 @@ The *expression* is the body of the function, the last expression of which gener
 
 ## Using Lambda Expressions
 
-Lambda expressions are especially useful when you want to perform operations on a list or other collection and want to avoid the extra work of defining a function. Many F# library functions take function values as arguments, and it can be especially convenient to use a lambda expression in those cases. The following code applies a lambda expression to elements of a list. In this case, the anonymous function adds 1 to every element of a list.
+Lambda expressions are especially useful when you want to perform operations on a list or other collection and want to avoid the extra work of defining a function. Many F# library functions take function values as arguments, and it can be especially convenient to use a lambda expression in those cases. The following code applies a lambda expression to elements of a list. In this case, the anonymous function checks if an element is text that ends with specified characters.
 
 [!code-fsharp[Main](~/samples/snippets/fsharp/lang-ref-1/snippet302.fs)]
 
+The previous code snippet shows both notations: using the `fun` keyword, and the shorthand `_.Property` notation.
+
 ## See also
 
 - [Functions](index.md)

samples/snippets/fsharp/lang-ref-1/snippet302.fs

@@ -1,2 +1,5 @@
-let list = List.map (fun i -> i + 1) [ 1; 2; 3 ]
-printfn "%A" list
+let fullNotation = [ "a"; "ab"; "abc" ] |> List.find ( fun text -> text.EndsWith("c") )
+printfn "%A" fullNotation         // Output: "abc"
+
+let shorthandNotation = [ "a"; "ab"; "abc" ] |> List.find ( _.EndsWith("b") )
+printfn "%A" shorthandNotation    // Output: "ab"