topic Re: Search and extract a string based on a keyword (Perl Expression) in SAS Programming

Search and extract a string based on a keyword (Perl Expression)

geoonline — Mon, 28 Mar 2016 16:02:52 GMT

Hi Experts,

I have a variable that has different strings seperated by a pipe sign, Say as : VAR1 = STRING1|STRING2|STRING3 and so - on.

Where only one string will contain a KEYWORD --> "EXTRACT_ME".

And I would like to extract only the string that has EXTRACT_ME keyword. (an example is shown below)

I can defenitely achieve it with the help of a DO loop and serach for the KEYWORD in each string one by one and extract it.

But I'm looking for something more effieicnt that really need to put it in a do loop. Maybe Perl Expression?

Experts: Any advise? Appreciate your help.

INPUT_VAR	OUTPUT_VAR
FIRST STRING\|EXTRACT_ME[ABC]\|SECOND STRING	EXTRACT_ME[ABC]
STRING ONE\|EXTRACT_ME[ABCDEFG]\|STRING THREE\|STRING FOUR	EXTRACT_ME[ABCDEFG]

Re: Search and extract a string based on a keyword (Perl Expression)

Reeza — Mon, 28 Mar 2016 16:18:11 GMT

You can do it with a combination of string functions, but PERL will probably work better.

data have;
string="FIRST STRING|EXTRACT_ME[ABC]|SECOND STRING";output;
string="STRING ONE|EXTRACT_ME[ABCDEFG]|STRING THREE|STRING FOUR";output;
run;

data want;
	set have;
	loc= index(string, "EXTRACT_ME");
	if loc>0 then end= index(substr(string, loc), "|");
	want=substr(string, loc, end-1);
run;

Re: Search and extract a string based on a keyword (Perl Expression)

Astounding — Mon, 28 Mar 2016 16:49:29 GMT

You'll need a slight modification, since LOC > 0 should control execution of the remainder of the statements (not just one).

A similar possibility:

if loc > 0 then want = scan(substr(string, loc), 1, '|');

Re: Search and extract a string based on a keyword (Perl Expression)

Ksharp — Tue, 29 Mar 2016 03:05:01 GMT

What reason  force you to use PRX ?


data have;
string="FIRST STRING|EXTRACT_ME[ABC]|SECOND STRING";output;
string="STRING ONE|EXTRACT_ME[ABCDEFG]|STRING THREE|STRING FOUR";output;
run;
data want;
 set have;
 length want $ 200;
 pid=prxparse('/EXTRACT_ME\[\w+\]/oi');
 call prxsubstr(pid,string,p,l);
 if p then want=substr(string,p,l); 
 drop pid p l;
run;

Re: Search and extract a string based on a keyword (Perl Expression)

FreelanceReinh — Tue, 29 Mar 2016 10:13:21 GMT

Just in case you don't need the redundant "EXTRACT_ME[]," but only what's in the square brackets behind this keyword, you can modify Ksharp's Perl regular expression for example as follows:

pid=prxparse('/(?<=EXTRACT_ME\[)[^\]]+/oi');

This expression matches a sequence of one or more characters not equal to "]" after the text "EXTRACT_ME[" (case-insensitive).