topic Re: How do I select specific values in a string? in SAS Programming

How do I select specific values in a string?

_maldini_ — Sun, 21 Feb 2016 18:24:47 GMT

I have a variable that contains a string of 9 numbers as values (e.g. 0000000100, 1110000100, etc.). These 9 numbers represent individual values (1 or 0). They were generated by a survey using radio buttons. If there is a 1 in the first position, it indicates a "Yes" to question number 1. If there is a 0 in the second position, it indicates a "No" to question number 2.

I need to create 9 new variables from each of the values in the string.

Var1 will get a 1 if the value in position one is 1. It will get a 0 if the value in position one is 0.

Var2 will get a 1 if the value in position 2 is 1. Etc.

How can I select specific values in a string like this?

I apologize if my description is unclear. I am a relative novice.

Re: How do I select specific values in a string?

SASKiwi — Sun, 21 Feb 2016 18:41:24 GMT

data want;
  answer_string = '101010101';
  array answers (*) $ 1 A1-A9;
  do i = 1 to 9;
    answers(i) = substr(answer_string, i, 1);
  end;
run;

Re: How do I select specific values in a string?

_maldini_ — Mon, 22 Feb 2016 00:15:37 GMT

Thanks @SASKiwi. Can I ask you a few clarifying questions?

<answer_string = '101010101';> Does this define the name of the string? And the value? The actual value of the string is different for each observation. Subject 1 might have 101010101 while subject 2 might have 000010101. Do I need to account for that in this line?
What does the 1 in the array represent (After the $ and before the elements, A1-A9)?

Re: How do I select specific values in a string?

SASKiwi — Mon, 22 Feb 2016 02:13:47 GMT

Yes. I assigned it just one value so you could understand the solution more easily. Of course it changes for each observation. Do you already have a dataset with this string in it? If you do then just read it in with a SET statement.
The 1 is the length of the variables A1 to A9 - one character.

Re: How do I select specific values in a string?

_maldini_ — Mon, 22 Feb 2016 02:20:25 GMT

Got it. I guess I'm still not clear what to put here if the values are different from observation to observation.

Yes, I do have the data set and was planning on reading it in w/ a SET statement.

Re: How do I select specific values in a string?

SASKiwi — Mon, 22 Feb 2016 07:53:26 GMT

data want;
  set have;
  array answers (*) $ 1 A1-A9;
  do i = 1 to 9;
    answers(i) = substr(answer_string, i, 1);
  end;
run;

Re: How do I select specific values in a string?

_maldini_ — Fri, 04 Mar 2016 17:27:03 GMT

I am using this array again for a similar purpose, and need some additional help.

This time, the string is a maximum of 6 characters. Each value is 2 characters. In other words, a value of 010101 has 3 distinct values (01, 01, 01).

Ultimately, I want to create 3 new variables for each string:

IF VAR1=01 THEN NEW_VAR1=1; ELSE NEW_VAR1=0;

IF VAR2=01 THEN NEW_VAR2=1; ELSE NEW_VAR2=0;

Etc.

This code works for one variable:

DATA want;
	SET have;
	
	ARRAY answers (*) $ 2 VAR1-VAR3;
	DO i = 1 to 3;
	answers(i) = substr(_400203, i, 2);
	END;
	
	DROP 
	_400203
	i;
RUN;

But this code does not work for multiple variables (In this example there are only 2 variables (_400203 and_400204), but I want to use it w/ 44 variables.

DATA want;
SET have

ARRAY array_name (*) $ 2 VAR1-VAR6;
DO i = 1 to 6;
answers(i) = substr(_400203-_400204, i, 2);
END;

DROP 
_400203
_400204
i;
RUN;