What is the difference between lambda expressions and delegates?

Lambda expressions and delegates are both tools used for implementing functional programming, but there are some differences between them:

1. Lambda expressions use the keyword “lambda” followed by parameters and the implemented expression, whereas delegates are a type that can be used to declare and pass method references.
2. Different functionalities: Lambda expressions can be used to create anonymous functions, which can be defined and used directly in the code, while delegates are a mechanism for passing and calling methods as parameters, which can be used to implement event handling, callback functions, etc.
3. Lambda expressions do not have their own type, as their type is inferred from the context, unlike delegates which are a special type that need to be defined and declared beforehand.
4. Flexibility differs: Lambda expressions can directly capture variables from the context and use them in the expression, while delegates usually require variables to be explicitly passed into the method.

In general, Lambda expressions are more concise and flexible, suitable for simple functional programming scenarios; while delegates are more powerful and versatile, able to handle more complex callback and event handling logic.