Hello,
           
          Please use 
          modulo (%) operator:
           
           
          zStartDate 
          = Month()==01 AND Day() == 02 ; // Start Period on a Daily 
          Chart for example
           
          zStartDate 
          = ( BarsSince( zStartDate ) % 12 ) == 0;
           
          Plot(zStartDate * Close,"Start Date",6,6 | 
          styleNoLabel); // I got this far...
           
           
           
 
          
            ----- Original Message ----- 
            
            
            Sent: Sunday, January 13, 2008 
            5:51 AM
            Subject: [amibroker] Plot 
            Vertical Line at Trading_Day_Interval(n)
            
            How does 
            one code a loop to plot vertical line beginning on a 
            particular period in the past 
            and then 
            redraw the same vertical line at a given interval in (n) 
            Trading Periods so it does not fall on a weekend?  
            
            ( I 
            suppose if it falls on Saturday, plot on Friday before and if it 
            falls on Sunday, plot it on Monday.
             
            Let's 
            say I replot the vertical line every 12 days,but want to avoid 
            weekends...
             
            Is there 
            a better function that would take care of it for both intraday and 
            daily intervals?
             
            ////////////////// Vertical Line Plot 
            for Starting Seed
            zStartDate = Month()==01 AND Day() == 02 ; 
            // Start Period on a Daily Chart for 
            example
            Plot(zStartDate * Close,"Start Date",6,6 | 
            styleNoLabel); // I got this far...
             
            Thanks,
             
            Mr 
            Valley