What is the difference between strip, compress and trim?

[pooja215]

Hi ,

Could you tell me which function i cannot use for removing leading and trailing spaces from a character text?

Regards,

Pooja.

[LinusH]

The documentation is quite clear IMO. What is your doubt?

This can be quite easily tested by using hard coded string in a data step, with comparisons/putting using $HEX. format.

[pooja215]

Thanks for such an early response!
Which of the following cannot be used to "just" remove the leading and trailing spaces from character data?

* Strip

* Compress

* Trim
Regards,
Pooja.

[PeterClemmensen]

data test;
   string = '    AB C D  ';

   strip_var    = strip(string);
   compress_var = compress(string);
   trim_var     = trim(string);
run;

[Shmuel · Accepted solution]

Run next code and learn the result of each function:

data _null_;
    length text $15;
    format text $char15.;
    text = '  ab   cde  f   ';
    trim = '*'||trim(text)||'*';
    compress = '*'||compress(text)||'*';
    strip = '*'||strip(text)||'*';
    put trim= ;
    put compress= ;
    put strip=;
run;

Here's the output:

Spoiler

trim=*  ab   cde  f*
compress=*abcdef*
strip=*ab   cde  f*

 See also the doc:

• STRIP function - removes all leading and trailing blanks
• TRIM function - removes all trailing blanks
• COMPRESS function - removes all blanks (by default - specify options to remove other chars)

Editor's note: modified this reply to include helpful info from @RW9 and others.

[pooja215]

Thanks it really helped!!

[Patrick]

@pooja215

I guess this was in interview question. So now with all the information you've got, what would be your answer and why?

[pooja215]

It wasn't an interview question. I got the information about trim, strip and compress in more detail.
The answer to my question was trim, as it did not remove the leading space from my text.
Regards,
Pooja.

[Patrick]

If you're using the question as you've formulated it the 2nd time "Which of the following cannot be used to "just" remove the leading and trailing spaces from character data?" then also compress() couldn't get used as it removes ALL blanks and not only the leading and trailing ones.

The two ways that's normally done:

strip(<string>)

trim(left(<string>))

[RW9]

And what does the manual say?  This is not a "question" as such, but asking someone to repeat what is clearly written in the manual.  I will paste tehm below for you:

Strip:

http://support.sas.com/documentation/cdl/en/lrdict/64316/HTML/default/viewer.htm#a002295689.htm

Trim:

http://support.sas.com/documentation/cdl/en/lrdict/64316/HTML/default/viewer.htm#a000212226.htm

Compress:

http://support.sas.com/documentation/cdl/en/lrdict/64316/HTML/default/viewer.htm#a000212246.htm

Each page actually gives you examples of the use of each of them.  And links to other string compress/stripping functions which may be of use.