The => operator has the same precedence as the assignment operator = and is right-associative.
It is used to declare lambda expressions and also it is widely used with LINQ Queries:
string[] words = { "cherry", "apple", "blueberry" };
int shortestWordLength = words.Min((string w) => w.Length); //5When used in LINQ extensions or queries the type of the objects can usually be skipped as it is inferred by the compiler:
int shortestWordLength = words.Min(w => w.Length); //also compiles with the same resultThe general form of lambda operator is the following:
(input parameters) => expressionThe parameters of the lambda expression are specified before => operator, and the actual expression/statement/block to be executed is to the right of the operator:
// expression
(int x, string s) => s.Length > x // expression
(int x, int y) => x + y // statement
(string x) => Console.WriteLine(x)
// block
(string x) => {
x += " says Hello!";
Console.WriteLine(x);
}This operator can be used to easily define delegates, without writing an explicit method:
delegate void TestDelegate(string s);
TestDelegate myDelegate = s => Console.WriteLine(s + " World");
myDelegate("Hello");instead of
void MyMethod(string s)
{
Console.WriteLine(s + " World");
}
delegate void TestDelegate(string s);
TestDelegate myDelegate = MyMethod;
myDelegate("Hello");