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In this video, we will learn about index function in poverty and the practical use of the index in

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the real life project.

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So it is very important video.

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And please watch Dylan and you will learn a lot of useful tips and tricks.

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So here I took one dataset from the court cases.

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So here you can see there are we have four countries under different countries and then we have a dead

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column dead confirmed and recovered cases and we are interested in confirmed cases.

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So let's do it step by step.

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So the structure of this data set is we are having confirmed cases.

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So we have a running total of all the confirmed cases right in this.

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We don't have any information on the level.

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So first of all, we are interested in the confirmed column and confirmed column, dead column and the

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country column.

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So then we can just remove the other columns.

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And because it's very big, they're the size of this file is very big, so we don't need to render everything.

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So in this to the SEC, we are only interested in, for example, us.

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We just need to frater us.

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And here we have all the data that could belong to us.

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So here you can see.

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On the 22nd of January, we have one case than twenty third, we have again one, for example, if you

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look here, 3rd of March, we have one one eight.

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Guesses.

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So what are the actual guesses on 3rd of March, it will be one one eight minus 98, right?

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So we need to assess the value from the previous role, so.

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For example, if you look here, 98, the record is a 41 year old and the index is 440, right.

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Because the index start from the 08.

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From the position so how we can access this value, this record is very simple, we just need to click

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here effect's.

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And then we have to write in the curly bracket 40 write it to.

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And here you can see we record this record us unauthenticated is finding confirmed the number of cases

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98, but we are only interested in confirmed cases.

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So what we have right here, the name of the column is a confirmed.

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So a record 98.

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So if I copy the whole Syntex here.

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Copy and.

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Then I just need to delete custom and we need another column so that we can display value in a separate

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column.

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So what we will do, we need to add column, custom column, and you can write any name here and here.

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We need to paste.

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Right.

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So let's get.

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And here you can see the Ninety-eight is being repeated with every rule.

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But what we need the same value as we can see in the current column, we should get the same value in

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the custom column.

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So we need something like incremental op ed here, just like we do in the if she knows some other programming

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languages, the to develop and like in follow there is like is equal to zero is less than 10 and a plus

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plus.

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And then we put the incremental pressure here.

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So we need some kind of incremental operator here.

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So what we will do here, we just need to delete add column because we don't need to repeat the same

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value with every.

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So we will delete it.

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And there is one function like index column so we can apply this indexed column from like from zero

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to onward with the incremental one here you can see it is a zero.

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Let me show you in the if you click in the setting.

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So here you can see the starting index is zero and the increment is one.

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So we are getting with every increment.

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For example, if we need to increment one or two or three, then it will show values accordingly.

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If I say, OK, we need only increment of two, we will get zero two, four, six and so on.

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But we are interested in only increment one, right.

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OK, so we have incremental operating here and now try to get the same.

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So now we need to add one more column, custom column, for example, and we can again copy and paste

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the same expression that we had copied.

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So this is the name of the previous step and then the calibration that which record we want to get and

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from which column.

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Right.

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So, you know, this this whole thing text.

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If you don't know, you can watch my previous video, Barclaycard's.

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So here we need to.

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Instead of 40, we need to get this value dynamically.

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So I need to access one field here.

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So which field I need to access this fund, this index field, so how we can get in field from the from

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the table, that's a square bracket.

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And you can see index and it will start from zero.

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Here you can see zero one, two, three, four.

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First of all, it will qualify for the zero and we will get the record from the zeroth position, then

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one, then two and three.

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So because everything that we write here and our custom column, this expression repeated with every

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rule.

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Right.

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So we need to click.

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OK, so here you can see we are getting exactly the same records as we can see from the confirmed column.

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Right.

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So this is like if you see here, one one eight, we are getting it.

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So we are interested in the previous value.

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Right.

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If I say OK in the custom column, instead of getting value from zero to index, if I write here first,

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then let me assume it.

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If I write here index minus zero.

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Then a zero three zero minus one, it would be minus one and we will get nothing right.

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So and then it will go for the like for the fifth, first and then the fifth minus.

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One they fought for will always get the value from the previous.

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All right, so we just need to confirm.

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So here you can see now we are getting of 60 in front of 60.

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We're getting 58 the previous four.

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Then again, 74.

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And then in front of 74, we are getting 60.

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It is humid and you can see better than 98 inverted previous value 74.

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And here you can see previous value is 74.

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So we got one issue here.

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This is one error because there is no value available on the index, minus one.

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So what we can do here, we you have seen my my video of our error handling so we can, um, use here

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try if you don't know about this thing, you can maybe watch my video and you can see different ways

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of error handling and try and see if it is error.

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Otherwise

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then I will display it.

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Or I can right here, for example.

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Zero.

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Zero and a confirmed.

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So we can rename this column.

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Like previous

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previous cases.

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And if I add one more column, because some column.

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And the Huracan flight delay case is.

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And I can confirm minus previous cases there, so.

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OK, OK, so here you can see on this date, we are having only one case and.

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Just a minute here.

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OK, so here you can see we have private cases and delicacies and on the twenty third of January we

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have again won cases.

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So there is no change and we are getting zero because there was no new case on twenty third of January.

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Right.

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And then again on 24th of January, we have two cases because they are an intruder and two minus one

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one.

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So we are having one in the same way.

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Uh, you can watch here like in the first of March we are having seventy four point seventy four minus

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sixty eight on this date.

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We have total cases, six seventy four minus sixty eight.

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It will be six.

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So this is so in the spirit you have seen with the help of Index Collum, we can easily get the value

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from the previous.