controlling servo with help of light sensor module

Hello guys I am new to this electronics feild and I am in beginner stage
I was trying to point my servo to a position and it was successfully moving to that position... And I need that servo to stay in that new position... Instead of that as soon as the sensor doesn't read anything it goes back to initial position...
Can anyone help me in writing program such that the servo points and stay in that position..

Only update the servo's position when there is a valid reading. The if statement will let you decide that.

Post your code for more specific help.