topic Re: quotes in regexp in macros in SAS Programming

quotes in regexp in macros

ChrisNZ — Wed, 05 Aug 2015 02:30:14 GMT

Hi all,

I am validating values, looking for quoted single characters, except quoted quotes.

'a' yes

'"' no

'A no

Abc no

This works fine, but I had to fight the code to make it work.

Here b works, c doesn't.

%let a="'";

%put b=%sysfunc(prxmatch(/^(%str(%'|%"))[^%str(%"%')]\1$/,%superq(a)));

%put c=%sysfunc(prxmatch(/^(%str(%'|%"))[^%str(%'%")]\1$/,%superq(a)));

The only change is the order of the quotes in the regexp list expression. SAS wants them "closed" in the right order or gets confused.

This order should not matter (it is just a list), and does not matter in SAS code or when using prxparse:

%put d=%sysfunc(prxmatch(%sysfunc(prxparse(/^(%str(%'|%"))[^%str(%"%')]\1$/)),%superq(a)));

%put e=%sysfunc(prxmatch(%sysfunc(prxparse(/^(%str(%'|%"))[^%str(%'%")]\1$/)),%superq(a)));

I sent this to tech support, but was wondering whether anyone had encountered this / any comments / similar odd regexp cases.

Re: quotes in regexp in macros

Tom — Tue, 08 Sep 2015 16:26:54 GMT

You are working too hard to create the regex expression. Let's break it down. To match any character that is not a double quote you need [^"]. To match that surrounded by quotes you just need to add the quotes. To have that match the full string then you need at have ^ before and $ after. Plus you need the beginning and ending slashes. Since your single quotes are balanced and your unbalanced double quote is inside of single quotes then no macro quoting of the regex is required.

%let pos=%sysfunc(prxmatch(/^'[^"]'$/,%superq(a)));

Re: quotes in regexp in macros

ChrisNZ — Thu, 17 Sep 2015 12:23:56 GMT

Tom i think you missed the fact that the string can be singled quoted *or doubled quoted*. The double quote option was not obvious from my text though it was used in the second example.

Re: quotes in regexp in macros

ChrisNZ — Thu, 17 Sep 2015 11:52:26 GMT

Tech support as lodged a defect.