topic Re: Trying to use an array to simplify a calculation in SAS Programming

Trying to use an array to simplify a calculation

djk200399 — Fri, 05 Feb 2021 10:21:39 GMT

Hi, I am progressing through my code and have an annoyingly long calculation that is very repetitive, however, one element of it uses a calculation as a one off. I want to be able to simplify this so I am not writing it multiple times. I have included my test attempt code at the bottom to show what I was trying to do (but failing miserably)

data calc;
set withdrawal_data;
do wdwl_FC_1=((Bal_Oct20+(Bal_Oct20*Money_Out_1))+(Adjustments_1*1000000)); end;
do wdwl_FC_2 = ((wdwl_FC_1+(wdwl_FC_1*Money_Out_1))+(Adjustments_1*1000000));

wdwl_FC_3 = ((wdwl_FC_2+(wdwl_FC_2*Money_Out_2))+(Adjustments_2*1000000));

wdwl_FC_4 = ((wdwl_FC_3+(wdwl_FC_3*Money_Out_3))+(Adjustments_3*1000000));

wdwl_FC_5 = ((wdwl_FC_4+(wdwl_FC_4*Money_Out_4))+(Adjustments_4*1000000));

wdwl_FC_6 = ((wdwl_FC_5+(wdwl_FC_5*Money_Out_5))+(Adjustments_5*1000000));

wdwl_FC_7 = ((wdwl_FC_6+(wdwl_FC_6*Money_Out_6))+(Adjustments_6*1000000));

wdwl_FC_8 = ((wdwl_FC_7+(wdwl_FC_7*Money_Out_7))+(Adjustments_7*1000000));

wdwl_FC_9 = ((wdwl_FC_8+(wdwl_FC_8*Money_Out_8))+(Adjustments_8*1000000));

wdwl_FC_10 = ((wdwl_FC_9+(wdwl_FC_9*Money_Out_9))+(Adjustments_9*1000000));

wdwl_FC_11 = ((wdwl_FC_10+(wdwl_FC_10*Money_Out_10))+(Adjustments_10*1000000));

wdwl_FC_12 = ((wdwl_FC_11+(wdwl_FC_11*Money_Out_11))+(Adjustments_11*1000000));
end;

run;
*Note this goes on for 60 iterations so I have only included 12 here and in my test

I have done the first (different) calc separately in another dataset in my test to try and get round the issue with the following code but

get errors in the arrays bit. Please can you help resolve this for me as driving me mad again. If there is a better way to do this instead of the arrays please let me know.

data calc;
set wdwl_calc;
wdwl_FC_202010=((Bal_Oct20+(Bal_Oct20*Money_Out_202010))+(Adjustments_202010*1000000));
run;

data fcast;
set calc;
run;

data tester;
set fcast;

array money (202010:202109) Money_Out_202010 - Money_Out_202109;
array wdwl (202010:202109) Adjustments_202010 - Adjustments_202109;
array fcwdrawal(12);
array wdrwal (202010:202109) Withdrawal_FC_202010 - Withdrawal_FC_202109;
do i = 1 to 12;
fcwdrawal(i) = ((Withdrawal_FC_202010+(fcwdrawal(i)*money(i)))+(wdwl(i)*1000000));
end;
run;

Thank you

David

Re: Trying to use an array to simplify a calculation

Kurt_Bremser — Fri, 05 Feb 2021 10:47:27 GMT

From your code, I take it that you suffer from a bad dataset layout (data (dates) in structure (column names)).

You should first transpose that to a long layout, and then you do a running calculation with retained variables.

For help with the transposition, supply a short example of your dataset, ideally as a data step with datalines.

Re: Trying to use an array to simplify a calculation

Astounding — Fri, 05 Feb 2021 13:24:07 GMT

Your array dimensions are off.

(202010:202109)

This includes all integers in the range, such as 202013, 202014, all the way through 202099.

Re: Trying to use an array to simplify a calculation

djk200399 — Fri, 05 Feb 2021 13:39:10 GMT

So as the data has each element with a date and month in it ie 202010 for October 20 what would I need to change the dimensions to in order to get it to pull these through.

Re: Trying to use an array to simplify a calculation

PaigeMiller — Fri, 05 Feb 2021 14:28:05 GMT

@djk200399 wrote:

So as the data has each element with a date and month in it ie 202010 for October 20 what would I need to change the dimensions to in order to get it to pull these through.

Show us a portion of the data, following these instructions: https://blogs.sas.com/content/sastraining/2016/03/11/jedi-sas-tricks-data-to-data-step-macro/

Re: Trying to use an array to simplify a calculation

Tom — Fri, 05 Feb 2021 14:39:58 GMT

Fix the index into the array.

data tester;
  set fcast;
  array money Money_Out_202010 - Money_Out_202012 Money_Out_202101-Money_Out_202109;
  array wdwl Adjustments_202010 - Adjustments_202012 Adjustments_202101 - Adjustments_202109;
  array fcwdrawal [12];
  array wdrwal  Withdrawal_FC_202010 - Withdrawal_FC_202012 Withdrawal_FC_202101 - Withdrawal_FC_202109;
  do i = 1 to 12;
    fcwdrawal[i] = ((Withdrawal_FC_202010+(fcwdrawal[i]*money[i]))+(wdwl[i]*1000000));
  end;
run;

Re: Trying to use an array to simplify a calculation

djk200399 — Fri, 05 Feb 2021 16:46:43 GMT

Hi Tom,

So are you suggesting if I have an array with the multiple years noted next to it, as you have done here it should fix the issue?

I will give this a go on the code later on. Thank you

Re: Trying to use an array to simplify a calculation

djk200399 — Fri, 05 Feb 2021 17:00:25 GMT

Hi Tom,

I tried your suggestion but get an error saying array subscript out of range at line 30 column 20. I will try and sort the sharing of a dataset on Monday that way it might be easier to see what I am doing wrong !

Re: Trying to use an array to simplify a calculation

djk200399 — Wed, 24 Feb 2021 17:12:28 GMT

I have transposed my datasets (which I know do all the time when reading them in from excel) to improve things but need to work out how to do this via an array.

I have 2 data sets that look like this

Dataset A
no	brand	product	period	acc
1	A	Regular	202010	300
2	A	Fixed	202010	350
3	B	Regular	202010	250
4	B	Fixed	202010	200
5	C	Regular	202010	150
1	A	Regular	202011	250
2	A	Fixed	202011	250
3	B	Regular	202011	400
4	B	Fixed	202011	200
5	C	Regular	202011	150
1	A	Regular	202012	150
2	A	Fixed	202012	160
3	B	Regular	202012	300
4	B	Fixed	202012	200
5	C	Regular	202012	400
1	A	Regular	202101	450
2	A	Fixed	202101	325
3	B	Regular	202101	350
4	B	Fixed	202101	275
5	C	Regular	202101	190

Dataset B
no	brand	product	period	int
1	A	Regular	202011	10
2	A	Fixed	202011	12
3	B	Regular	202011	12
4	B	Fixed	202011	10
5	C	Regular	202011	15
1	A	Regular	202012	20
2	A	Fixed	202012	13
3	B	Regular	202012	12
4	B	Fixed	202012	5
5	C	Regular	202012	7
1	A	Regular	202101	2
2	A	Fixed	202101	11
3	B	Regular	202101	3
4	B	Fixed	202101	3
5	C	Regular	202101	14
1	A	Regular	202102	12
2	A	Fixed	202102	12
3	B	Regular	202102	12
4	B	Fixed	202102	10
5	C	Regular	202102	10

I want to use the 2 datasets to undertake an ongoing calculation

The first dataset is one that was created last month with forecast numbers going forward from an actual position in 202010

The second is the new calculation that needs to take place on this dataset but using the prior month result

So in the case of no1 the first calc should be acc for 202010 from dataset A plus int for 202011 from dataset B. The second calc should use the outcome of the first calc as it's starting point and then add int for 202012 from dataset B and so on until the end.

How do I use the result of each calc for the next calculation simply and efficiently ?

What I should see here results wise using no1 as an example is

	calc
202011	310
202012	330
202101	332
202102	344

I hope this makes sense and would an array work to do this or am I over complicating things??

Thanks in advance of your help again

Re: Trying to use an array to simplify a calculation

PaigeMiller — Wed, 24 Feb 2021 17:19:55 GMT

Repeating my earlier request to you in this thread

Show us a portion of the data, following these instructions: https://blogs.sas.com/content/sastraining/2016/03/11/jedi-sas-tricks-data-to-data-step-macro/

Re: Trying to use an array to simplify a calculation

djk200399 — Thu, 25 Feb 2021 10:12:49 GMT

I have tried running the said macro but it does not work in my SAS given some of the internal restrictions. Instead I have attached the two datasets (simplified versions) as csv's for a quick upload.

So for these I need a calculation of acc from accrual dataset at 202010 + the value of calc from the all1 dataset for 202011 merged by the no1 field and then the next calculation will be the last calculation we did + value of calc from the all dataset for 202012 merged by the no1 field and so on.

Appreciate your help on this.

Re: Trying to use an array to simplify a calculation

Kurt_Bremser — Thu, 25 Feb 2021 11:34:32 GMT

proc sort
  data=ds_a (where=(period='01oct2020'd))
  out=ds_a_
;
by brand product;
run;

proc sort
  data=ds_b (where=(period ge '01nov2020'd))
  out=ds_b_
;
by brand product_period;
run;

data want;
merge
  ds_a_
  ds_b_
;
by brand product;
if first.product
then calc = acc;
calc + int;
keep brand product calc;
run;

Untested, for lack of usable data.

Re: Trying to use an array to simplify a calculation

Kurt_Bremser — Thu, 25 Feb 2021 11:51:06 GMT

There is no variable int in any of your CSV's.

PLEASE POST USABLE DATA.

(which fits your descriptions, or adapt the descriptions to the data)

Re: Trying to use an array to simplify a calculation

djk200399 — Thu, 25 Feb 2021 13:45:06 GMT

Apologies for not including the correct data, I managed to do a similar solution to yours Kurt so apologies for the failure on my part