topic Re: Find special characters in a string, take them off and do a calculation, and put them back in in SAS Programming

Find special characters in a string, take them off and do a calculation, and put them back in

gsk — Fri, 24 Jan 2020 15:07:46 GMT

I want to find special characters in a string, remove them from the string, do a calculation, and put that characters back in. Is there an elegant way to do this?

For example, if I have a variable with values:

33.3%

16%

<10%

I want to multiply 1.2 after removing either or both % and <

39.96

19.2

and then I need to put the special characters back

39.96%

19.2%

<12%

Maybe we can use index and prxmatch functions..? index(lborres,'<') or index(lborres,'%') ; if prxmatch('m/<|%', lborres) > 0 then do; I'm not sure how I should go about this (or other way)..

Re: Find special characters in a string, take them off and do a calculation, and put them back in

ballardw — Fri, 24 Jan 2020 16:05:55 GMT

You won't be able to do this if just remove special characters but you would need to store things like the < somewhere. If all of the values are percentages then putting them back is relatively simple but you may need to address concerns about how many digits to maintain in your re-calculated values. So please specify rules for significant digits.

Note that because you will be adding digits to a character value that you should also tell us what the defined length of the variable is. If the current defined length of a variable is 5 characters then you won't be able to fit 39.96% into the variable as that requires 6 character positions.

Re: Find special characters in a string, take them off and do a calculation, and put them back in

Amir — Fri, 24 Jan 2020 16:09:39 GMT

Are you looking for something like the following? The answer should be in the variable called "result".

data have;
   input text $char10.;
   datalines;
33.3%
16%
<10%
;


data want;
   set have;
   length result $ 10;
   retain factor 1.2;

   number  = compress(text,'.','kd');
   product = number * factor;
   result  = tranwrd(text,cats(number),cats(product));
run;

Kind regards,

Amir.

Re: Find special characters in a string, take them off and do a calculation, and put them back in

PaigeMiller — Fri, 24 Jan 2020 16:10:32 GMT

I would recommend a little different approach.

You can eliminate from the string any character that is not a number and not a decimal point and not a negative sign via the COMPRESS() function.

Once you have done that, you can use INPUT to turn these character strings into actual numbers, so you can do the multiplication.

Then I would leave them as numbers, and use some format to make the number appear with a % sign or with a < indicator.

Re: Find special characters in a string, take them off and do a calculation, and put them back in

Amir — Fri, 24 Jan 2020 17:50:46 GMT

I meant to convert variable number to a number, which is why I used the cats() function on it later which formats numerics with the best. format.

Using a format did cross my mind, but some data had one symbol and others had two and it wasn't immediately clear to me what the rule was from what the OP had posted.

Kind regards,

Amir.

Re: Find special characters in a string, take them off and do a calculation, and put them back in

gsk — Fri, 24 Jan 2020 19:40:29 GMT

I can set up rounding and character lengths in another part of the program; should they affect the code/solution? This solution worked. Thank you!

Re: Find special characters in a string, take them off and do a calculation, and put them back in

PaigeMiller — Fri, 24 Jan 2020 20:10:44 GMT

@Amir wrote:

I meant to convert variable number to a number, which is why I used the cats() function on it later which formats numerics with the best. format.

Using a format did cross my mind, but some data had one symbol and others had two and it wasn't immediately clear to me what the rule was from what the OP had posted.

Kind regards,

Amir.

I like your solution @Amir , it is very compact and efficient.

With regard to my suggestion to use formats: my general feeling is that numbers ought to be numbers, and if you want a % sign on the end or a < in front, I would certainly use formats for that, although your solution makes it easy to turn it back into character variables with the special symbols. Obviously, if there were a huge set of possible special symbols, like for example if the original text string was '~2.2}', you can't accomodate all these special symbols using formats.

Re: Find special characters in a string, take them off and do a calculation, and put them back in

Amir — Mon, 27 Jan 2020 09:41:59 GMT

Thanks for marking a post as a solution (not everyone does).

For best practice, I would recommend assigning variable "number" a numeric value before using it in a calculation. That also means you don't have to assign variable "number" a character length (which I didn't do, because I meant to make it a numeric variable).

Further, as @PaigeMiller also pointed out, if you have negative values then "-" can be added to the second argument of the compress() function.

An example implementation of both points is:

   number  = input(compress(text,'.-','kd'),8.);

Kind regards,

Amir.

Re: Find special characters in a string, take them off and do a calculation, and put them back in

anuajax — Tue, 06 Jul 2021 08:15:30 GMT

What if special characters are present in between?

want to mask name with Officer12345 keeping special characters

like (Mr). Briane 'O' Conor to (Of).ficer1'2'345

one more example Han & Van to Off & icer12345

Re: Find special characters in a string, take them off and do a calculation, and put them back in

Amir — Tue, 06 Jul 2021 09:51:59 GMT

Hi @anuajax,

Ideally, it is best practice to create a new question with what you are now asking and you can supply a link back to this question for context.

For each example you have given what result do you want to see and what did you get when you tried the existing solution?

Also, when supplying data, it is a lot easier for everyone to help you if you supply data using a data step with datalines, as can be seen in the solution.

Thanks & kind regards,

Amir.