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