topic Re: Arrays Basics in Statistical Procedures

Arrays Basics

robertrao — Tue, 25 Sep 2012 18:13:21 GMT

Hi Team,

I am not good at using arrays.

Below is an example. I want to know the exact meaning of balance=balance+ (balance*rate{month});

I also was having the notion that when evet i use an array statement I had to go for do i=1 to n;

In the below example there was no need of it and got the answer.

Please help me understand

Thanks

data trial;
input balance month;
cards;
500 3

500 4

760 2

500 1

800 3

400 6

500 6

300 7

;

run;

data trial2;

set trial;

array rate {6} _temporary_ (0.05 0.08 0.12 0.20 0.27 0.35);

if month ge 1 and month le 6 then

balance=balance+ (balance*rate{month});

run;

OUTPUT:

balance month

500 3

600 4

820.8 2

525 1

896 3

540 6

675 6

300 7

Re: Arrays Basics

robertrao — Tue, 25 Sep 2012 18:21:56 GMT

I was thinking that the position in the rate corresponds to value of the month when we write rate{month}.

Please correct me if I am wrong???

Also why there is no need of a do i= step??????????

Thanks

Re: Arrays Basics

Linlin — Tue, 25 Sep 2012 18:24:49 GMT

Hi Karun,

your output is incorrect.

with "rate {6} _temporary_ (0.05 0.08 0.12 0.20 0.27 0.35);"

we have rate1=0.05,rate2=0.08 ... ,rate6=0.35.

first observation (balance=500, month=3):

balance=500 +(500*rate(3))=500+(500*0.12)=560

Re: Arrays Basics

robertrao — Tue, 25 Sep 2012 18:28:00 GMT

Good Linlin,

I made a typo i a hurry. shd have been 560

Thanks

Re: Arrays Basics

robertrao — Tue, 25 Sep 2012 18:31:34 GMT

So the position number for example 0.20 holds a position 4

so this value is to be taken for multiplication if the month value is 4?????????

Thats the meaning of rate{month}.???????????????

Thanks

Re: Arrays Basics

Linlin — Tue, 25 Sep 2012 18:37:22 GMT

Yes. That is correct.

Re: Arrays Basics

robertrao — Tue, 25 Sep 2012 18:41:42 GMT

Great help Linlin

Thanks

Re: Arrays Basics

robertrao — Tue, 25 Sep 2012 18:44:26 GMT

Also why was there no need of a do loop

do i=1 to n????????????

Thanks

Re: Arrays Basics

data_null__ — Tue, 25 Sep 2012 18:55:39 GMT

An array is just a variable list that you reference with an index. Usually we use an array so we can do the same operation OVER the entire ARRAY (list of variables). But that is not always the case as in your example where the index comes from the value of month and changes for each observation. In this case it serves as a lookup table. Also since your array is temporary there is no actual variable list, but that doesn't change how the elements are referenced.

Re: Arrays Basics

art297 — Tue, 25 Sep 2012 19:04:49 GMT

Linlin: Reply to this post so that I can be the first one to congratulate you for attaining Master status!

Re: Arrays Basics

robertrao — Tue, 25 Sep 2012 19:05:39 GMT

Thanks data_null_

for your detailed explanation

Re: Arrays Basics

robertrao — Tue, 25 Sep 2012 19:12:19 GMT

I can ask linlin another one.if she doesnt mind.............jus kidding.

You are all very helpful

Re: Arrays Basics

robertrao — Tue, 25 Sep 2012 19:17:56 GMT

Hi Arthur,

I have a problem understanding the code. It was answerd in the Forum and they said this is one of the classic examples. I posted it yesterday but there was no response. Could you help me with that please. If i get your consent I can post it again.

Thanks

Re: Arrays Basics

Linlin — Tue, 25 Sep 2012 19:26:43 GMT

Thank you Art and I just bought the whole thing to make wine or mead (Starter
Winemaking Equipment Kit w/ Floor )! - Linlin

Re: Arrays Basics

art297 — Tue, 25 Sep 2012 19:28:58 GMT

Congratuations! Send me a bottle when its ready!

Re: Arrays Basics

Linlin — Tue, 25 Sep 2012 19:30:22 GMT

Sure!

Re: Arrays Basics

robertrao — Tue, 25 Sep 2012 21:47:25 GMT

Hi Team,

I have this code while reading the paper 242-30 (Arrays made easy) and want to know whats the meaning of i=1

this code was explained for common errors and muisunderstandings so dont worry too much about :do until (i gt 24);

data dailytemp;

set tempdata;

array temperature_array {24} temp1-temp24;

array celsius_array {24} celsius_temp1-celsius_temp24;

do until (i gt 24);

i = 1; /*referring to this line of the code*/

celsius_array{i} = 5 / 9 * (temperature_array{i} – 31);

end;

i=0;

drop i;

run;

Thanks

Re: Arrays Basics

art297 — Tue, 25 Sep 2012 22:38:42 GMT

Something is missing from the code .. i never gets incremented.

You really should start a new discussion when you have a new question.

When you do, post all of the code. i=1 simply sets a variable called i to the value of 1.