title: use of !! in Call Symput in SAS
body: <p>Could anyone tell me what this data step is doing? I have never seen the use of "!!" or a "double exclamation mark" before?</p>
  
  <pre><code>data _null_;
  set &amp;dset_in.;
  if i = _n_ then do i=1 to nvar;
      call symput ("var" !! strip(put(_n_, 3.)), strip(Variabile));
      call symput ("min" !! strip(put(_n_, 3.)), strip(lim_inf));
      call symput ("max" !! strip(put(_n_, 3.)), strip(lim_sup));
  end;
  run;
  </code></pre>
  
  <p>A general gist of the loop would be helpful too, thanks</p>