Decimall Float Question

[morc]

hey,

I have float values that look something like this when they are
printed:
6.0E-4
7.0E-4

I don't want them to be like this I want them to be normalized with 4
decimal places.

If anybody can show me how to do this it would be greatly appreciated.
Thanks in advance.
-morc

[electrician]

// Roundoff routine for 4 decimal places
// used someplaces.

function round(x) {
return Math.round(x*10 000)/10000;
}

[morc]

thanks
but can somebody guide me on how to do this with BidDecimal.
I've been looking through the documentation and I can't figure it out.

thanks in advance.

[Lasse Reichstein Nielsen]

"morc" <qu************ *@msn.com> writes:

I have float values that look something like this when they are
printed:
6.0E-4
7.0E-4

I don't want them to be like this I want them to be normalized with 4
decimal places.

If you want to control the representation, you will need to construct
the strings yourself.

One suggestion:
function roundToString(n , decCount) {
var intpart = ((decCount == 0) ? Math.round : Math.floor)(n);
var res = String(intpart) ;
if (decCount > 0) {
var fracPart = n - intpart;
var offset = Math.pow(10,dec Count);
var string = String(Math.rou nd((1 + fracPart)*offse t));
res += "."+string.subs tring(1);
}
return res;
}

It has its limits as well, since it uses Javascript's internal
number-to-string operation at places, but for reasonable sizes
(e.g. 0-10 digits on each site of the decimal points) it should
work.

/L
--
Lasse Reichstein Nielsen - lr*@hotpop.com
DHTML Death Colors: <URL:http://www.infimum.dk/HTML/rasterTriangleD OM.html>
'Faith without judgement merely degrades the spirit divine.'

[morc]

oh geez... i did not realise i was posting in a javascipt group.
I'm sorry this isn't a java script problem please ignore this post.

[Dr John Stockton]

JRS: In article <bq**********@h otpop.com>, dated Tue, 4 Apr 2006
19:12:22 remote, seen in news:comp.lang. javascript, Lasse Reichstein
Nielsen <lr*@hotpop.com > posted :

One suggestion:
function roundToString(n , decCount) {
var intpart = ((decCount == 0) ? Math.round : Math.floor)(n);
var res = String(intpart) ;
if (decCount > 0) {
var fracPart = n - intpart;
var offset = Math.pow(10,dec Count);
var string = String(Math.rou nd((1 + fracPart)*offse t));
res += "."+string.subs tring(1);
}
return res;
}

It has its limits as well, since it uses Javascript's internal
number-to-string operation at places, but for reasonable sizes
(e.g. 0-10 digits on each site of the decimal points) it should
work.

Not for negative numbers (try on (0.0 - RoundingError)) ; could be made
to fail better for large positive ones, NaN, infinity, undefined.

The OP should have read the newsgroup FAQ; see below. Section 4.6
treats the topic and has links.

The rounding of exactly-representable half-way cases may need
consideration.

<FAQENTRY> Rename 4.6 to remove the "2", since the article is more
general. </FAQENTRY>

ISTM that fracPart = n % 1

I don't think I have a method using 1+fracpart .. substring(1) in js-
round.htm at present.

--
© John Stockton, Surrey, UK. ?@merlyn.demon. co.uk Turnpike v4.00 IE 4 ©
<URL:http://www.jibbering.c om/faq/> JL/RC: FAQ of news:comp.lang. javascript
<URL:http://www.merlyn.demo n.co.uk/js-index.htm> jscr maths, dates, sources.
<URL:http://www.merlyn.demo n.co.uk/> TP/BP/Delphi/jscr/&c, FAQ items, links.

[RobG]

el*********@ele ctrician.com said on 05/04/2006 2:45 AM AEST:

// Roundoff routine for 4 decimal places
// used someplaces.

function round(x) {
return Math.round(x*10 000)/10000;
}

Using your function:

round(123.12394 99999999); // gives 123.1239

but:

round(123.12394 999999999); // gives 123.124
Do you know why your function does that?
--
Rob
Group FAQ: <URL:http://www.jibbering.c om/FAQ>

[Dr John Stockton]

JRS: In article <bq**********@h otpop.com>, dated Tue, 4 Apr 2006
19:12:22 remote, seen in news:comp.lang. javascript, Lasse Reichstein
Nielsen <lr*@hotpop.com > posted :

function roundToString(n , decCount) {
var intpart = ((decCount == 0) ? Math.round : Math.floor)(n);
var res = String(intpart) ;
if (decCount > 0) {
var fracPart = n - intpart;
var offset = Math.pow(10,dec Count);
var string = String(Math.rou nd((1 + fracPart)*offse t));
res += "."+string.subs tring(1);
}
return res;
}

roundToString(1 .994, 2) 1.99
roundToString(1 .996, 2) 1.00

--
© John Stockton, Surrey, UK. ?@merlyn.demon. co.uk Turnpike v4.00 MIME. ©
Web <URL:http://www.merlyn.demo n.co.uk/> - FAQish topics, acronyms, & links.
I find MiniTrue useful for viewing/searching/altering files, at a DOS prompt;
free, DOS/Win/UNIX, <URL:http://www.idiotsdelig ht.net/minitrue/>

[Lasse Reichstein Nielsen]

Dr John Stockton <jr*@merlyn.dem on.co.uk> writes:

roundToString(1 .994, 2) 1.99
roundToString(1 .996, 2) 1.00

Whoops. Just ignore that an I'll try again. :)

function roundToString(n umber, positions) {
var e = Math.pow(10,pos itions);
var s = String(Math.rou nd(number*e));
var offset = s.length - positions;
return s.substring(0,o ffset) + "." + s.substring(off set);
}

/L
--
Lasse Reichstein Nielsen - lr*@hotpop.com
DHTML Death Colors: <URL:http://www.infimum.dk/HTML/rasterTriangleD OM.html>
'Faith without judgement merely degrades the spirit divine.'

[RobG]

Lasse Reichstein Nielsen said on 07/04/2006 6:46 AM AEST:

Dr John Stockton <jr*@merlyn.dem on.co.uk> writes:

roundToString(1 .994, 2) 1.99
roundToString(1 .996, 2) 1.00

Whoops. Just ignore that an I'll try again. :)

function roundToString(n umber, positions) {
var e = Math.pow(10,pos itions);
var s = String(Math.rou nd(number*e));
var offset = s.length - positions;
return s.substring(0,o ffset) + "." + s.substring(off set);
}

/L

That still has issues, e.g.:

roundToString(1 .015, 2) 1.01
roundToString(1 .025, 2) 1.02
roundToString(1 .035, 2) 1.03
roundToString(1 .045, 2) 1.05
roundToString(1 .055, 2) 1.06
It seems to me that the only way to properly round numbers is to treat
them as a string and round as a human would: to round to n places, look
at the n+1 digit and round right-to-left from there.

The use of Numbers and any kind of decimal arithmetic introduces inaccuracy.
--
Rob
Group FAQ: <URL:http://www.jibbering.c om/FAQ>