topic Concatenate in do loop with keep blanks doesn't work in SAS Programming

Concatenate in do loop with keep blanks doesn't work

optimus — Thu, 29 Jun 2017 07:44:44 GMT

I try to concatenate a text-string with a do loop. the functions catt, cats and catx works, but cat doesn't. but i need the blanks in the ouptut string.

data want;

	length string_in string_out_cat string_out_cats string_out_catt string_out_catx $200 c $1;

	string_in = "this is a textstring";
	do i = 1 to lengthc(string_in);
		c = substr(string_in,i,1);
		string_out_cat = cat(string_out_cat,c);
		string_out_cats = cats(string_out_cats,c);
		string_out_catt = catt(string_out_catt,c);
		string_out_catx = catx("*",string_out_catx,c);
	end;

	

run;

any ideas?

Re: Concatenate in do loop with keep blanks doesn't work

RW9 — Thu, 29 Jun 2017 09:13:24 GMT

This is due to the way strings are handled. When you set a new variable of a given length, say 5 in this case then the variable is:

[][][][][]

Now if you choose the procedure that keeps blanks and concatenates variables and add ABCDE:

[][][][][][a][b][c][d][e]

Then put that back into the chracter that has length 5 it chops the end off, hence the variable can only contain 5 spaces.

Thus the question back to you is what do you expect the output to look like? is it a space between words, or letters? If its words then you would be better off doing:

data want;
  ...
  do i=1 to countw(string," ");
    word=scan(string,i," ");
  end;
run;

If its each letter, then catx() would be the function. But without further info I can't say.

Re: Concatenate in do loop with keep blanks doesn't work

optimus — Thu, 29 Jun 2017 10:02:00 GMT

Thanks for your answer. This was the hint I needed. Now it make sence.

I want to keep the space between the word, but I have to loop / process each letter. So the final solution is this:

data want (drop=c i ablank);

	length string_in string_out $50 c $1;

	string_in = "this is a textstring";
	ablank=0;

	do i = 1 to lengthc(string_in);
		c = substr(string_in,i,1);
		
		if ablank=1 then string_out = cat(strip(string_out)," ",c);
		else string_out = cat(strip(string_out),c);
		
		if c=" " then ablank=1;
		else ablank=0;
			
	end;

run;