How to change the font of the numbers in a tex

Question

I've read the below answer : Font selection in XeTeX for specific characters

but I need a solution that works with pdflatex instead of xetex.

Answer 1

There is no correspondent in pdflatex of the “interchar tokens” feature of XeTeX. Making digits active for expanding them to add a font call is not a choice, as you want digits also for things like \linebreak[2] which would break painfully.

The only way out is to define a macro:

\newcommand{\printnum}[1]{{\fontfamily{...}\selectfont#1}}

where ... should be the family name of the font you want to use; then, to print a number with that font, say

\printnum{42}