RE: bike shifting - output decimal in percent

[Drew Adams]

> How do I output a decimal float digit
> 0 <= x <= 1 into percent? ("A percentage?"
> Correct English?)
> 
> But I wonder if/why-not there is/isn't
> a built-in way to do it?

Use function `format'.  See `C-h f format' and
(elisp) `Formatting Strings'.

E.g.
(setq foo  0.314159265358979)

(format "%2.14g%%" (* 100.0 foo))
 => "31.459265358979%"

(format "%2.2g%%" (* 100.0 foo))
 => "31%"