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Collections are used to organize data so that it can be used efficiently.
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Hello and welcome to C# collections.
0:04
I'm Jeremy in this course will be learning
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all about how to work with data
in various types of collections.
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Collections are used to organize data so
that they can be used efficiently.
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A more common term for
a collection is a data structure and
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you'll find that I use
the terms interchangeably.
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In C# we call them collections.
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It's very difficult to write
any sort of software program
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without using a collection at least once.
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In fact,
if you've taken the prerequisites for
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this course,
then you're already familiar with arrays.
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An array is a type of collection.
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You may have also heard of lists,
sets, and dictionaries.
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These are the most common
types of collections.
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Although the title of this
course is C# collections.
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The collections we'll discuss here are all
actually provided by the .NET framework,
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which means they can be
used by any .NET language.
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We'll be using C# as we explore them.
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There are dozens of different
types of collections.
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You might be wondering why there are so
many different types.
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They each have advantages and
disadvantages.
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Basically most collections support
four fundamental operations,
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Insert, Access and Find,
Update, and Delete.
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One way we can evaluate a collection
is by how quickly it can perform
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each of these operations.
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So when we decide which one to use,
we should consider when and
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how often we need to
perform these operations.
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Because the job of a collection is
to store data efficiently, we also
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want to consider how much additional space
it needs in order to store each item.
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The amount of data the collection
will store is also a factor.
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Some are efficient for
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small to medium amounts of data, and
others are better for larger sets.
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Additionally some collections can store
items in the order we add them and
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others, can't.
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So if we want to maintain
an ordered list of items,
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we probably want to pick the collection
that can do that for us.
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Something else to consider is how quickly
we can copy the items from one collection
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into another.
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This is actually very important
because the way we store
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data in our programs while
we're working with it
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is often different than the way that
the data is displayed to a user.
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As you can see,
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there are many things to consider
when picking which collection to use.
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You may be thinking,
this seems like a lot of hassle.
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Isn't there a collection out there
that we can use for everything?
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The answer to that question depends
on how much data you're working with.
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If you're only storing a few items and
the amount of data isn't going to grow,
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then it doesn't really matter
which collection you use.
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Just pick the one that
simplest to work with.
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Picking the correct collection for
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the job doesn't really become important
until the amount of data you're working
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with starts to affect
the performance of the computer.
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However, it's sometimes
difficult to predict
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how much data a program will
have to deal with in the future.
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A couple dozen items in
a collection may not be a big deal.
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Depending on how often it's being used but
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it's not uncommon to be working
with thousands of items or
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even larger collections, especially in the
age of big data sets that we live in now.
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That's just one more thing to
consider when picking a collection.
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I found it important to know about many
different types of collections, so
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that I can pick the right one for the job.
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In fact a very common question
asked in job interviews
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is which collection would you use
to solve a given problem and why.
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In this course we'll learn about four
of the most common types of collections
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arrays, lists, sets, and dictionaries.
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Learning how these work can
help you start to understand
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how other types of
collections work as well.
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In the end of this course, we'll use what
we've learned to create an application
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that translates text into Morse
code messages and back again.
3:57
To start,
let's take a deeper look at arrays in C#
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