How to get previous value that no. of bars larging than MA20?

[chunwai]

Hello,
How to get previous value that no. of bars larging than MA20 ?

noOfDaygtMA20 = BarsSince( C<=MA(Close,20) ); //calcuate close price is larger than MA20

AddColumn( C, "Close" );
AddColumn( noOfDaygtMA20, "calculate close >=MA20" );