note Ratazong <p>Hi [SerZKO]!</p> <p>Your hash-key does not need to be a static string, but could be constructed <em>on the fly</em> with a variable containing a counter. Check the following example <code> my %e; my $max = 4; foreach my $nr (1..$max) { $e{"uid_$nr"} = $nr; } </code> For your problem, you may either add a the number of available UIDs in your data-structure (and use it like the <c>$max</c> in the example above), or you might check with [doc://exists] whether a specific UID-entry is present in your hash (e.g. <c>if (exists($e{"MEX$nr"}) { ... }</c>)</p> HTH, Rata 987716 987716