topic Re: Write codes to show increment of a sequence in SAS Programming

Write codes to show increment of a sequence

di_niu0 — Thu, 13 Jul 2023 02:29:53 GMT

Hi all. I would like to transform table 1 to table 2.

Table 2 means the bigger value has to times all the previous values. How do I write the code to show such increment? Thanks!

Table 1:

Value1 Value2 Value3

5 6 7

Table 2:

Value1 Value2 Value3

5 5*6 5*6*7

Write efficient code for a sequence

di_niu0 — Thu, 13 Jul 2023 00:48:45 GMT

Hi all. I would like to write codes to transform table from Table 1 to Table 2. Thank you!

Table 1:

ID Value1 Value2 Value3

1 1 2 3

2 4 5 6

3 7 8 9

Table 2:

ID Value4 Value5 Value6

1 1-(1-1) 1-(1-1)(1-2) 1-(1-1)(1-2)(1-3)

2 1-(1-4) 1-(1-4)(1-5) 1-(1-4)(1-5)(1-6)

3 1-(1-7) 1-(1-7)(1-8) 1-(1-7)(1-8)(1-9)

Re: Write efficient code for a sequence

ballardw — Thu, 13 Jul 2023 01:28:48 GMT

Are the (1-1)(1-2) supposed to be multiplication? And follow normal rules of arithmetic order such as the result of 1-(1-1)(1-2) is 1 - (result of (1-1) times (1-2) )?

I ask because we get inconsistent usages.

What metric are you using to define "efficient"? Fewer lines of code? Execution time? Memory use? Some combination of these?

If this is a subset of a larger problem you should say so because your number of variables is low enough that you don't gain much in different approaches that might appear if there were 50 values per observation.

Re: Write efficient code for a sequence

di_niu0 — Thu, 13 Jul 2023 02:31:23 GMT

Hi I've write another post to ask the question more clearly. https://communities.sas.com/t5/SAS-Programming/Write-codes-to-show-increment-of-a-sequence/m-p/884599#M349484

Re: Write codes to show increment of a sequence

SASKiwi — Thu, 13 Jul 2023 04:10:10 GMT

Looks like you are drip feeding us part of an unspecified bigger problem. With only 2 variables needing calculation just hard-code the result:

data Have;
  Value1 = 5;
  Value2 = 6;
  Value3 = 7;
run;

data Want;
  set Have;
  Value2 = Value2 * Value1;
  Value3 = Value3 * Value2;
  put _all_;
run;

Or if this example is going to grow then here is a more flexible way:

data Want;
  set Have;
  array values (3) Value1 - Value3;
  do i = 1 to 2;
    Values(i+1) = Values(i+1) * Values(i);
  end;
  put _all_;
run;

Re: Write codes to show increment of a sequence

Kurt_Bremser — Thu, 13 Jul 2023 06:03:18 GMT

Use an array:

data want;
set have;
array v {*} value:;
do i = 2 to dim(v);
  v{i} = v{i} * v{i-1};
end;
drop i;
run;

Re: Write codes to show increment of a sequence

di_niu0 — Thu, 13 Jul 2023 14:22:55 GMT

What if I have many values? How to expand v{i} = v{i} * v{i-1}; ?

Re: Write codes to show increment of a sequence

di_niu0 — Thu, 13 Jul 2023 14:37:42 GMT

Got it. Thanks!