Replace Third Character from Left in a String in JSL

[#1]

I would like to take a column with a string in it, and in each row, replace the third character from the left with a "9." How might I go about this using JSL?

[#2]

Here is the simple script

Names Default To Here( 1 );

dt = Current Data Table();

For Each Row(
	dt:YourColumn = Substr( dt:YourColumn, 1, Length( dt:YourColumn ) - 4 ) || "9" ||
	Right( dt:YourColumn, -2 )
);

I strongly suggest that you take the time to read the Scripting Guide, so that you will have the background knowledge that will allow you to solve these questions