[Tex/LaTex] How to swap the commands for two symbols

Question

I find that I much prefer \varphi to \phi and generally would rather use the \varphi than the \phi. But it's three more characters to type \varphi instead of \phi, which is most troublesome. So I would like to swap the two commands. I tried a couple of things on my own, but one resulted in an infinite loop in compilation and the other led to \varphi taking over all of the \phi commands I made. What would be the correct way to do this?

Answer 1

Try the following:

$\phi\varphi$
\let\temp\phi
\let\phi\varphi
\let\varphi\temp
$\phi\varphi$