# meaning of variable equal dot [closed]

I came across a program which I have written in a simplified form.

For[i=1,i<100, i=i+1;
func = a x^i;
func=.
];


What is purpose of "func=."?

## closed as off-topic by MarcoB, b3m2a1, Michael E2, J. M. will be back soon♦Mar 29 '18 at 1:20

This question appears to be off-topic. The users who voted to close gave this specific reason:

• "This question arises due to a simple mistake such as a trivial syntax error, incorrect capitalization, spelling mistake, or other typographical error and is unlikely to help any future visitors, or else it is easily found in the documentation." – MarcoB, b3m2a1, Michael E2, J. M. will be back soon
If this question can be reworded to fit the rules in the help center, please edit the question.

• A tip: whenever you encounter an unfamiliar symbol like =. in Mathematica, highlight it and press F1. – J. M. will be back soon Mar 28 '18 at 17:29
• =. removes any rules defined for the left-hand-side. – David G. Stork Mar 28 '18 at 17:54
• – AccidentalFourierTransform Mar 28 '18 at 23:33

=. removes any rules defined for the left-hand side.