How to set report field invisible?

I have create various textbox with sourceExp link to array variable (decimal type) which read data from table field value (decimal type).

I have format the textbox to zero decimal for display purpose.

May i know how to set textbox value to "nil" (blank, instead of 0), if value = 0?

I can't hide whole section because other array variable value may not read as 0.


Please help.

beginner.