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Function Parameters
5:12In this video we’ll learn how to create our own higher order functions in Scala. We will create our own example function, which will take another function as a parameter.
Scala provides us with a wide array
of built in, higher order functions.
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Most of the time, we'll make use
of these built in functions.
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However, there may be times where we want
to create our own higher order function.
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Let's take a look at how to do that.
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In an earlier video,
we created a map which holds the name and
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ranking of our avengers.
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Let's create a higher order function
which takes three avengers and
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compares their ranking by
finding the men and the mask.
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Let's copy the avengers map
we have created earlier.
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Now let's take out the rankings from
these and store them into variables.
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Awesome.
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Now we have the three rankings.
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Let's use them in our function.
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Great.
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We've created a function called compare,
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which takes three arguments that are
integers and has a function noted by f:
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that takes these three arguments and
combines them to one.
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There are several ways we
can invoke such a function.
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Passing the values of the rankings for
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each Avenger, along with the function we
would like to use to compare the three.
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First, let's get an idea of which one
of our avengers has the best ranking.
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In this example,
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we're comparing the three arguments passed
in by finding the minimum between them.
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Remember our compare function
takes a function parameter
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which accepts a three arguments.
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The function we pass to compare is the min
function with underscores as wildcards
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which represent avenger1,
avenger2 and avenger3.
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Let's recompile our code and
check out our results.
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As expected,
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we get eight as a result, which is
the minimum ranking between our Avengers.
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A ranking of eight belongs
to Captain America.
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Captain America is our best ranked
Avenger, as his value is closest to one.
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Similarly, we can pass another function
and find out the worst ranked Avenger.
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In this case,
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we compared the three arguments passed
by finding the maximum between them.
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Remember, our compare function
takes a function parameter
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which accepts three arguments.
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The function we passed to compare is
the max function with underscores as
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wildcards which represent avenger one,
avenger two, and avenger three.
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Let's check out the results.
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Awesome, as expected we got the ranking
that's furthest away from one between our
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three avengers.
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Cool.
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Not only did we learn about how to
use higher-order functions, but
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we also learned how to create our own.
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In the next video,
we'll discuss another topic, closures.
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See you there.
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