topic Re: sas add substring to an existing string in SAS Programming

sas add substring to an existing string

ilikesas — Thu, 13 Oct 2016 03:02:51 GMT

Hi,

suppsose I have a variable string with value name1.

I would like to add to this string ***, like this the string becomes name1***.

I tried to do:

string = string ||"***";

but it didn't work, I had to create a dummy variable and do dummy = string ||"***"; and delete the original string and rename the dummy string. But is there a direct way to add a substring to an existing string without having recourse to dummy variables?

Thank you!

Re: sas add substring to an existing string

Astounding — Thu, 13 Oct 2016 03:16:58 GMT

You can do it directly:

string= trim(string) || '***';

You're running into trouble because STRING is already defined with a fixed length. If you just concatenate without adding the TRIM function, the trailing blanks remain in place and there isn't room to add any more characters.

Re: sas add substring to an existing string

ilikesas — Thu, 13 Oct 2016 04:11:01 GMT

I am still getting errors, namely in the cases where I have strings which are made entirely of numbers, so if I have something like this: 14.793 and want to get 14.793*** I can't.

But when I do a = string||'***'; I get 14.793*** even without trimming.

Thank you!

Re: sas add substring to an existing string

Reeza — Thu, 13 Oct 2016 05:09:41 GMT

Post your exact code and log. Note that your code above doesn't use the TRIM function.

Following the suggestions of assigning a long enough LENGTH and use of the TRIM function I can't replicate your issue. In general, I prefer the CAT family of functions since they trim automatically. I also find it easier to read.

data test;
	length a b $20.;
	input a $ b $;
	datalines;
14.793 15.697
;
run;

data test2;
	set test;
	a=trim(a)||"***";
	b=catt(b, "****");
run;

proc print data=test2;
run;

Re: sas add substring to an existing string

Kurt_Bremser — Thu, 13 Oct 2016 09:11:43 GMT

@ilikesas wrote:

I am still getting errors, namely in the cases where I have strings which are made entirely of numbers, so if I have something like this: 14.793 and want to get 14.793*** I can't.

But when I do a = string||'***'; I get 14.793*** even without trimming.

Thank you!

If your original variable is defined as type character with a length of 6, and contains the value '14.793', then it cannot accept any further characters.

Since your new variable a is automatically defined by SAS with sufficient length (because you concatenate with a string literal, so SAS knows exactly how many characters are needed), it can take the whole new string.

Example:

data have;
string = '14.793';
run;

proc contents;run;

data want;
set have;
a = string !! '***';
run;

proc contents;run;

Partial output from the second proc contents:

Alphabetic List of Variables and Attributes

       #    Variable    Type    Len

       2    a           Char      9
       1    string      Char      6

Re: sas add substring to an existing string

Astounding — Thu, 13 Oct 2016 14:13:07 GMT

That result is misleading. It would occur when STRING is actually a numeric variable, not a character variable. There is no way to add "***" to the value fo a numeric variable (although a format might be able to get it to print with "***" at the end). When your original variable is character, you won't get any errors.

Re: sas add substring to an existing string

ilikesas — Sat, 15 Oct 2016 02:10:09 GMT

That is my case - I get errors that my variable is numeric, although I did try to convert it to character in the following way:

estimate = put(estimate,12.3.);

Re: sas add substring to an existing string

Astounding — Sat, 15 Oct 2016 02:36:00 GMT

Once ESTIMATE is defined as numeric, it remains numeric. Forever. Yes, the PUT function generates a character string, but SAS then has to store those characters in a numeric variable, so SAS converts the character string to numeric.

Re: sas add substring to an existing string

ilikesas — Sat, 15 Oct 2016 02:43:22 GMT

So yes, the only way to make ESTIMATE character is to create a new character DUMMY variable, make it equal ESTIMATE, delete the original ESTIMATE and then rename DUMMY to ESTIMATE. That is what I did in the very beginning, but I just thought if there was another way to make it directly. I accepeted as a solution the post where the string and catt functions are shown, making it more useful for future readers.

Thank you!