topic Re: regular expression (prxparse) question in SAS Programming

regular expression (prxparse) question

gzr2mz39 — Fri, 20 Jul 2018 17:47:16 GMT

How would I create a regular expression using prxparse that always starts with x1, ends with y2 and the middle part can be any length (1+) and any characters?

For example, I want:

x1abc_efy2

x12y2

x1a!y2

I don't want:

x2abcy2

x1zy3

Thank you.

Re: regular expression (prxparse) question

kiranv_ — Fri, 20 Jul 2018 18:35:31 GMT

something like below. here ^ means starting position where we have x1 as requirement. .+ indicates any character after the starting position and ? stops reading once it find any other character mentioned in regex. $ means at the last position and here we have y2 as per requirement

 DATA want;  
    IF _N_ = 1 THEN PATTERN_NUM = PRXPARSE("/^x1.+?y2$/");  
 
RETAIN PATTERN_NUM; 
    INPUT STRING $30.;    if PRXMATCH(PATTERN_NUM,trim(STRING))= 1 then output; 
	drop pattern_num;
DATALINES; 
x1abc_efy2
x12y2
x1a!y2
x2abcy2
x1zy3
;

Re: regular expression (prxparse) question

Astounding — Fri, 20 Jul 2018 18:37:20 GMT

Looks like the parsing guys are on vacation today. If it would help, here's a way to do it without parsing:

x1 = index(var, 'x1');

y2 = index(var, 'y2');

if y2 > x1 > 0 then newvar = substr(var, x1, y2 - x1 + 2);