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Make sure you've got our birds list
loaded in this C# REPL for this video.

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Most of our LINQ operators
return an Enumerable,

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what if we needed to be something
else like a list or an array?

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The one I use most often is ToList,

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birds.Where b goes to

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b.color equals Red and
then I will call ToList.

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Its usefulness might
not be apparent though,

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remember when we talked
about deferred execution.

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Since we're in the C# REPL, our queries
are getting evaluated immediately.

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If we assign a LINQ
expression to a variable,

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var redBirds equals birds.Where
b goes to b.Color equals Red.

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It doesn't get evaluated
until we iterate on it.

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So calling ToList or
any of the other conversion operators

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iterates through the sequence
to produce the result.

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And so our query is executed.

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RedBirds.ToList.

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Similarly, there's ToArray.

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RedBirds.ToArray and now we have an array.

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There's a few more conversion operators
that can be useful in some edge cases,

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like if you need a lookup or
a dictionary.

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I've linked to those in the notes.

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You should check them out and think about
how you could use them in a LINQ query.

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>> Wow,
that's a lot of operators we just used.

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Did you take notes?

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I find myself constantly looking up syntax
and documentation on LINQ operators,

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especially for
ones I don't use very often.

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We learn to use quantifiers
to see if a sequence contains

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elements that fit a condition.

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Element operators to pick single
elements out of a sequence.

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We use partitioning operators to
obtain a subset of a sequence and

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joins to join multiple sequences together.

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We performed aggregations
to analyze our sequences.

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We use set operations to remove duplicates
and merge separate sequences into one.

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We then learned we can use
LINQ to generate sequences and

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finally, to convert them to
different types of sequences.

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We've been working in
workspaces this whole time.

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You'll find that as you advance to
coding in an IDE like Visual Studio.

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The built in features will help you
remember the usage without having

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to look up the documentation.

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Let's take a quick peek
at how using an IDE

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can help us jog our memories
when writing LINQ queries.

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>> I've got a blank console
application here in Visual Studio,

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let's create a list of
numbers like we did earlier.

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Var numbers equals new list of int and

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we'll initialize it, 2,

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4, 8, 16, 32, 64.

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Okay, so
we don't have the System.Linq namespace.

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Let's look at what Visual Studio's
IntelliSense tells us we can call

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on the numbers variable.

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So you'll notice we don't have any of
the LINQ methods we've been using.

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Just the normal list methods, so

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let's add the System.Linq namespace
using System.Linq.

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Now, I'll type a period and it gives us
a lot more methods, look at all those.

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So notice the little
arrow icon right here.

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If I click on this, that arrow is
indicating that it's an extension method.

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And you can see here that
we've got the definition and

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the syntax for each of these.

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Let's call the Where operator,
we've used that a lot.

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Where n goes to n is greater than 10.

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If I hover over the n here,

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notice that it's telling me
the n parameter is an integer.

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How helpful is that?

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It can be really useful
when writing LINQ queries.

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So you see how Visual Studio gives
us a lot of documentation, so

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we don't necessarily have to go and
find it ourselves.

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What a huge help.