From: Gavin Kistner <gavin@...>
Date: 2005-11-01T23:36:36+09:00
Subject: Re: Newbie: How to format a number to always show two decimals?

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On Oct 31, 2005, at 5:41 PM, David A. Black wrote:
> Aside to Phrogz: is that left over from a game of code golf?? :-)

LOL. No, before I grokked sprintf, I needed the round_to =20
functionality. That's a port of the Number.toFixed algorithm from =20
section 15.7.4.5 of the ECMAScript (ECMA-262) specs:

15.7.4.5   Number.prototype.toFixed (fractionDigits)
Return a string containing the number represented in fixed-point =20
notation with fractionDigits digits after the decimal point. If =20
fractionDigits is undefined, 0 is assumed. Specifically, perform the =20
following steps:

1. Let =C4 be ToInteger(fractionDigits). (If fractionDigits is =20
undefined, this step produces the value 0).
2. If =C4 < 0 or =C4 > 20, t hrow a RangeError exception.
3. Let x be this number value.
4. If x is NaN, return the string "NaN".
5. Let s be t he empty string.
6. I f x =B3 0, go to step 9.
7. Let s be "-".
8. Let x =3D =D0x.
9. I f x =B3 10^21, let m =3D ToString(x) and go to step 20.
10. Let n be an integer for which the exact mathematical value of n =D6 =20=

10^=C4 =D0 x is as close to zero as possible. If there are two such n, =20=

pick t he larger n.
11. I f n =3D 0, let m be the string "0". Otherwise, let m be the =20
string consisting of the digits of the decimal representation of n =20
(in order, with no leading zeroes).
12. If =C4 =3D 0, go to step 20.
13. Let k be the number of characters in m.
14. If k > =C4, go to step 18.
15. Let z be the string consisting of =C4 +1=D0k occurrences of the =20
character =D40=D5.
16. Let m be the concatenation of strings z and m.
17. Let k =3D =C4 + 1.
18. Let a be the first k=D0=C4 characters of m, and let b be the =20
remaining =C4 characters of m.
19. Let m be the concatenation of the three strings a, ".", and b.
20. Return the concatenation of the strings s and m.




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