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Let's build a query to find out how many bird sightings we have for birds that are endangered.
Since we're tracking
our bird sightings and
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conservation status, let's write
a query to see how many sightings
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have been reported of birds that
are at risk of becoming endangered.
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Make sure you've got your birds list and
your C# REPL.
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First, let's check out the different
conservation statuses the birds have.
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for statuses equals birds.Select,
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b goes to b.Conservationstatus and
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then I call Distinct so
I remove the duplicates statuses.
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So we've got least concerned,
endangered, vulnerable,
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near threatened and critically endangered.
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We only want to concern ourselves
with the endangered statuses So,
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why don't we take out least concerned and
near threatened.
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Let's reassign it the same variable but
without those statuses.
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So statuses = statuses.Where
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s goes to s is not equal to
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"LeastConcern" and
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s is not equal to "NearThreatened".
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Okay, so now our statuses has
only what we want to deal with.
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We'll need to access
the sightings of birds and
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then only get those that
are in our list of statuses.
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I bet there are a lot of
ways we can achieve this.
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The first thing I think of when I've
got two different collections is a join
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we can join our list of birds
to the status as a variable
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then we'll only get the birds
that have that status.
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FarendangeredSightings equals
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start with birds.join statuses
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I'll do a new line here.
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So our outer key would be birds b goes to
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b.ConservationStatus facial and
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then our inner key selector
From our statuses list,
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s => s, cuz it's just strings.
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All right, now for our result.
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I'll just use the two input parameters (b,
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s) => I'm gonna create
a anonymous type here
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new status equals s and
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birds equals b, okay.
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Let's see what that gives us.
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EndangeredSightings.
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We've got lists of birds, but
now we need the sightings.
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Well we could actually put in sightings
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inside our anonymous objects to get
the sightings instead of the birds.
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So I'm gonna use my Up arrow key to get
most of the query back so I can reuse it.
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B goes to B dot conservation status.
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Then S goes to S but
here I'm going to do B S
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goes to new we'll keep the statuses.
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We like statuses.
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Equals s but
this time I'm gonna say Sightings
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equals b.Sightings.
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Okay, let see what that gives us,
endangered sightings.
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So we've got one element for each bird.
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We need to group them and
then get a total count for each status.
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So let's group by status.
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So var endangered sightings.
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Actually how about I clear the console?
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Okay, and then I'm gonna use my up
arrow key again to get my history.
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var endangeredSightings
= birds.Join(statuses,.
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Yep, looks good.
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b => b.ConservationStatus and then.
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S goes to S.
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But then I'll do b, s goes to
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new status.
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Actually we're gonna do the same thing.
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I coulda used my arrow key.
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But that's okay.
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Status = s and then Sightings
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= b.Sightings then I'm
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going to call .GroupBy
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b goes to b.Status because,
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Our anonymous type here, the property
is status so we're gonna group by that.
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Okay, and endangeredSightings.
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All right.
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Well it looks like our statuses are there,
and our sightings Okay we do have
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a group it's a little hard to see like
this so let's do that same query again.
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I'm gonna clear the console.
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All right, endangeredSightings b goes to
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b.ConservationStatus s
goes to s then that but
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then, instead of returning sightings,
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let's do a select here
.Select b goes to new.
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Then we'll do Status = b.Key
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which should be our status, right,
because we just did the GroupBy Status.
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Next it's key and then the Sightings
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is going to be equal to the b.Sum and
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then s goes to s.Sightings .Count.
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So we're gonna get the sum of the count of
the sightings for each grouping by status.
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Then we need to curly brace
to end our anonymous type and
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then close the Select method and Okay,
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let's see what we get
now endangeredsightings.
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All right, great.
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We've got 14 sightings
of endangered birds.
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29 are vulnerable and
12 of critically endangered.
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Looks like I misspelled endangered.
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[LAUGH]
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