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[MUSIC]

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Welcome to Introducing Dictionaries,

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I'm Ashley Boucher and
I'll be your teacher for this course.

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Before moving forward, take a second
to check the teacher's notes and

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make sure you've completed all of
the prerequisites for this course.

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Remember, any questions you have can
be asked in the Treehouse community.

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The community is also a great
place to help other students and

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answer their questions as well.

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Ready to get started?

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In this course you're going to learn about
a new type of Python data structure,

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the dictionary.

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A dictionary is a set of key value pairs.

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Think of a Python list, an ordered
sequence of comma separated values,

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indexed by numbers.

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A dictionary does have
similarities to a list.

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For instance, dictionaries also
contain comma separated values,

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but that's really where
the similarities end.

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In a dictionary, each of its
values has a label called the key.

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And dictionaries are not sequences,
they aren't ordered.

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They're indexed by their keys,
not numbers.

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You'll see variations of dictionaries in
just about every programming language.

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You might know them as associative
arrays or associative memories.

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They're the earliest stepping
stone in thinking about object

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oriented programming,

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a design pattern that revolves around
modeling reusable objects in your code.

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It's an exciting topic,

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join me in the next video to start
learning more about key value pairs.