Dear all,<br><br>Most probably due to very limited experience in programming and in working with gretl I&#39;m<br>currently stuck with the following issue:<br><br>I have a data file with time series of monthly returns of AEX stocks from 1973 to 2007. By using<br>

a script (attached and probably not the most elegant) I&#39;m trying to accomplish 2 things:<br><ol><li>Count the number of &quot;valid&quot; stocks, that is stocks which have 12 months of returns data prior to t=0.</li>
<li>
Only the stocks which fulfil the above mentioned criteria should be copied to a new data file (appended).<br></li></ol>Can anyone please explain to me how to accomplish #2 because just with &quot;store&quot; instruction the data gets<br>

overwritten.<br clear="all"><br>-- <br>---------------------------------------<br>Sergey<br>