From: K Livingston
Subject: Re: how to suppress tailing zeros with FORMAT ~F
Date: 
Message-ID: <7108f7d9-b8e4-452a-9ab0-8e7de7ef4a0c@p2g2000prf.googlegroups.com>
On Jan 20, 10:23 am, jimka <·····@rdrop.com> wrote:
> (format nil "~4,3F" some-number)
> will print eactly 3 digits after the decimal, if some-number is 3.2,
> then it prints 3.200.  How can i tell format to
> supress the trailing 0's?  anybody know?
> obviously i could as format to print to a string, then post-process
> the string... but maybe there's an easier way.
>
> -jim


Format ~4,3F is a little weird, by the way,.. you are not going to get
a leading zero either for 0.211 unless you give it ~5,3 since the
decimal point is counted against the first parameter.

Assuming the leading zero is ok... simply just ~4F (or ~5F) seems to
do (mostly) what you want except when it's just 3.2 or something like
3.201 you will get " 3.2", (note the leading space) since you forced
it to be 4 characters wide.  if you can tolerate that?  that's
probably your best bet.

As an alternative to Alexander's function of consing up the format
string you could put your number through a function that just lops off
precision below the level you wanted before passing it to simply
format ~F.

Kevin