Gain insights into LINQ in C#, learn about lambda expressions, explore common LINQ methods, avoid pitfalls, and refactor code to be more expressive and efficient.

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LINQ is the best feature in C#. If you’re interested in writing more expressive code to work with collections, this course is for you. In this course, you will learn about what LINQ is and what lambda expressions are. You will learn the most common LINQ methods and some common pitfalls to avoid when using LINQ. You will also write your first methods using LINQ and use LINQ to refactor some common constructs.

Getting Started with LINQ in C#

# `Count` instead of `Any`

We should always prefer `Any` over `Count` to check if a collection has any elements, or at least one element, that meets a condition.

Let's write `movies.Any()` instead of `movies.Count() > 0`.

The `Any` method returns when it finds at least one element that meets the condition, but the `Count` method evaluates the entire query.

# `Where` followed by `Any`

We can use a condition with `Any` directly, instead of filtering first with `Where` to then use `Any`.

Let's write the following line:

```csharp
movies.Any(movie => movie.Rating == 5)
```

We’ll use the above line instead of this one below:

```csharp
movies.Where(movie => movie.Rating == 5).Any()
```

The same applies to the `Where` method followed by `FirstOrDefault`, `Count`, or any other method that receives a filter condition. We can use the filter condition directly instead of relying on the `Where` method.

# `FirstOrDefault` without `null` checking

Let's always check if we have a result when working with `FirstOrDefault`, `LastOrDefault`, and `SingleOrDefault`.

When any of the three above methods don't find results, they return the default value of the collection type.

For objects, the default value would be a `null` reference. And you know what happens when we access a property or method on a `null` reference---



 Learn basic mistakes when working with LINQ and how to fix them.

Common Mistakes and What to Do

Learn basic mistakes when working with LINQ and how to fix them.

Getting Started

LINQ Method: Where

Common LINQ Methods

Syntax & Pitfalls

Refactor with LINQ

What's New in LINQ?

Wrap-up!

Common Mistakes and What to Do

`Count` instead of `Any`

`Where` followed by `Any`

Common Mistakes and What to Do

Count instead of Any

Where followed by Any

`Count` instead of `Any`

`Where` followed by `Any`