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It is a common pattern in programming
to take one data type and

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convert it into another data type.

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Sets fit into this pattern when
it comes to pre-processing data.

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For example,
let's take a list of random integers

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where some of the values
are repeated in the list.

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So we've got some threes,
some ones, some twos, and

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they're in no particular order here.

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Now, imagine trying to remove
the duplicates from this list

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without using sets.

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We can work through this together,

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we can pseudocode the steps
required to remove the duplicates.

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Pause me, and I'll let you try it first,
and then I'll show you how I did it.

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How did it go?

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Was it challenging?

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Here's what I came up with.

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My strategy is to iterate
through the list of integers and

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then collect the unique
values into a new list.

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First I sort the original list.

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It's easier to process data if you sort
it first before doing more calculations.

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Then I loop through the sorted list.

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Since the list is sorted, every time
the loop moves to the next element,

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I can compare it to the previous element.

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On each step of the loop, for the first
step I just put that number into a new

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list because there's nothing to
compare when it's just the first one.

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For every next number, I compare it
to the last number in the new list.

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If the values are equal then I can pass,
I don't need to do anything.

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If the values are not equal, then I
put that number in the new list, and

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what happens is that I can end with
a list of no duplicate numbers.

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You can check my teacher's notes
to see my implementation code.

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That was quite the mental exercise.

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Fortunately, it's not as
complicated with sets.

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Let's scroll back up to see
our list of numbers again.

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This time, let's just pass that list
into the set constructor function.

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And we'll print this out as well.

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So for now, I've printed out a set
of the numbers, we can see one,

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two and three,
all of the duplicates are just gone.

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I can use the sorted function
to convert it back into a list.

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So here, Let's say

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numbers equals a set of numbers.

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First we convert our list into a set,

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then numbers equals sorted numbers,

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we convert our set back into a list.

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Now watch what happens
when I print out numbers.

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I have a list of one, two, and three.

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It's in order.

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And it's all of the unique numbers
there are no duplicates here.

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These two functions, sorted and
set can also be chained together

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very easily to clean any list of
duplicated data in one line of code.

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I'll show you what that looks like.

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So we can say unique numbers

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equals sorted set of numbers,

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we can print our unique numbers.

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And in the console,
I can run my script again to get 1, 2 and

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3, my list of unique numbers
in a very pythonic manner.

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So, we've just learned how to use the set
constructor function to make an empty set.

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And to make a set from an iterable and

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we explored more in-depth about how
using sets can simplify data processing.

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when duplicates need to be
removed from a collection.

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Now, we're ready to learn about set
specific methods and operations.

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In the next video,
we will learn the basics of adding and

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removing elements from a set.