Arrow symbol which is used to define a function. vertical line is attached to a tail (endpoint where no tip) of an arrow

Question

I found the following arrow notation in the Type Theory and Formal Proof: An Introduction

How can I depict(draw) it using Tex?

I've browsed to find it but failed to.

Answer 1

Just use \mapsto in math mode.

I knew now that this symbol is used in mapping.