topic Re: Flagging when a String is within another String in SAS Programming

Flagging when a String is within another String

publicSynechism — Mon, 17 Jun 2019 20:19:58 GMT

I want to take a dataset like this:

data have;
	input a $ b $;
	datalines;
123abc one
123abc two
123abc 123abc45
;
run;

And flag when variable 'a' is fully contained within variable 'b',

such that I return this table:

data want;
	input a $ b $ flag;
	datalines;
123abc one 0
123abc two 0
123abc 123abc45 1
;
run;

Thanks

Re: Flagging when a String is within another String

Reeza — Mon, 17 Jun 2019 20:35:11 GMT

Have you tried the FIND() or INDEX() functions?

@publicSynechism wrote:

I want to take a dataset like this:
data have;
	input a $ b $;
	datalines;
123abc one
123abc two
123abc 123abc45
;
run;
And flag when variable 'a' is fully contained within variable 'b',

such that I return this table:
data want;
	input a $ b $ flag;
	datalines;
123abc one 0
123abc two 0
123abc 123abc45 1
;
run;
Thanks

Re: Flagging when a String is within another String

tsap — Mon, 17 Jun 2019 20:48:44 GMT

I believe this will accomplish the results you are looking for:

DATA WORK.WANT;
	SET WORK.HAVE;
		 IF FIND(TRIM(b),TRIM(a),'i') GE 1 THEN DO; FLAG=1;	END;
	ELSE IF FIND(TRIM(b),TRIM(a),'i') LT 1 THEN DO; FLAG=0; END;
RUN;

Hope this helps.

Re: Flagging when a String is within another String

Reeza — Mon, 17 Jun 2019 20:53:05 GMT

It can be as simple as:

FLAG = find(b, a, 'it') GE 1;

Re: Flagging when a String is within another String

publicSynechism — Mon, 17 Jun 2019 20:53:47 GMT

Yes, but I believe it's returning 0 whether it finds the string or not, since it will return the start position of the found string. It will always be the case in my data that startpos = 0.

data have2;
	set have;
	out=find(a,b,'t');
	out2=index(trim(a),b);
run;

Re: Flagging when a String is within another String

Reeza — Mon, 17 Jun 2019 21:03:53 GMT

@publicSynechism wrote:

Yes, but I believe it's returning 0 whether it finds the string or not, since it will return the start position of the found string. It will always be the case in my data that startpos = 0.
data have2;
	set have;
	out=find(a,b,'t');
	out2=index(trim(a),b);
run;

Which is why the check is for Greater than or equal to 1.

From the documentation:

The FIND function searches string for the first occurrence of the specified substring, and returns the position of that substring. If the substring is not found in string, FIND returns a value of 0.

Setting the flag as follows will always return a 0 or 1.

FLAG = find(b, a, 'it') >= 1;

Re: Flagging when a String is within another String

Ksharp — Tue, 18 Jun 2019 13:21:24 GMT

data have;
	input a $ b $;
	flag=ifn(find(b,a,'it'),1,0);
	datalines;
123abc one
123abc two
123abc 123abc45
;
run;