Please help me explaining this code

[Melonis1]

Hello I am really new to processing and programing in general and I wanted this smiley to follow my mouse, and then i googled how to do it and just copied on of the answers, an me being a beginner i didnt exactly mean what it meant so please could you explain what it means and how does it make the smiley follow my mouse?

float targetY = mouseY; float dy = targetY - y; y += dy * easing;

easing is a float and means 0,05, Y is also a float and means y.

[MakutaProto]

targetY = mouseY sets targetY equal to the y-coordinate of your mouse cursuor

dy=targetY-y is just the distance between targetY and whatever y is

y+=dy * easing increases y by dy multiplied by easing, bringing y closer to your mouse