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