Add support for fractionalizing common decimals

[qJake]

It would be awesome if there were support for fractionalizing certain numbers. I know it's a pretty short extension method, but I already use Humanizer elsewhere so this would be a great addition for me.

Examples:

1 -> 1
1.25 -> 1 1/4
2.5 -> 2 1/2
4.33 -> 4 1/3
1.8 -> 1 4/5
0.75 -> 3/4

Optionally, you could use the ASCII fraction characters when possible:

1 -> 1
1.25 -> 1¼
2.5 -> 2½
4.33 -> 4 1/3
1.8 -> 1 4/5
0.75 -> ¾

What I'm not sure of is how far you'd want to go ... personally, I don't see a benefit to fractionalizing anything beyond fifths (0.2).

[qJake]

Here's the method I ended up writing, I'm sure it has some edge cases and bugs but it's probably a good start:

        public static string Fractionalize(this decimal dec)
        {
            string fractionalPart = (dec - Math.Truncate(dec)).ToString("0.00");
            string wholePart = ((int)Math.Floor(dec)).ToString();

            if (fractionalPart == "0.00")
            {
                return wholePart;
            }

            string result = dec > 1 || dec < 0 ? wholePart : "";

            switch (fractionalPart)
            {
                case "0.20":
                    result += " 1/5";
                    break;
                case "0.25":
                    result += " ¼";
                    break;
                case "0.30":
                case "0.33":
                case "0.34":
                    result += " 1/3";
                    break;
                case "0.40":
                    result += "2/5";
                    break;
                case "0.50":
                    result += " ½";
                    break;
                case "0.60":
                    result += "3/5";
                    break;
                case "0.66":
                case "0.67":
                    result += "2/3";
                    break;
                case "0.75":
                    result += " ¾";
                    break;
                case "0.80":
                    result += " 4/5";
                    break;
            }

            return result.Trim();
        }

[MehdiK]

Thanks for the suggestion @qJake.

This could be useful; although as you said I'm not sure how far one might want to push it and the desired behavior could get really subjective.

I'll keep this here asking users to vote on it. If enough people want it, we'll think about an implementation.

A couple of considerations:

• This should be localisable.
• It should deal with every fractional part and not just those listed in your switch case; i.e. what happens for 0.31 and 0.55?
• How do we allow configurability around rounding and precision?

[hazzik]

what happens for 0.31

31/100; 0.31; or 14/45

what happens for ... 0.55

11/20; 0.55; or 5/9

See this gist: https://gist.github.com/hazzik/4e292aba1b748e2271e7

[qJake]

You would probably have to specify some sort of tolerance, as well as a maximum fractional part. For example, 0.31, with a maximum fractional part of 5 and a tolerance of ±0.03 would yield "1/3", but the same number with a maximum fractional part of 50 would yield 14/45.

So the fractional part is the highest possible denominator, and the tolerance is the maximum amount, either way, that the number can be shifted to fit into a "nice" fraction (e.g. 0.33 / 0.34 for 1/3).

Number	Tolerance	Maximum Denominator	Output	Status
0.34	± 0.1	5	1/3	✅
0.34	± 0.0	5	0.34	❌
0.34	± 0.0	55	17/50	✅
0.3	± 0.4	3	1/3	✅
0.199	± 0.1	5	2/5	✅
0.199	± 0.1	3	0.199	❌
0.1	± 0.0	10	1/10	✅
0.11	± 0.0	10	0.11	❌

I realize this complicates the feature quite a bit, but if done right, this could be very useful! 😃

[MehdiK]

Sounds great to me. Show me the PR :p

[eytan600]

Hi, @MehdiK!
As of today, there is still no support for the conversion of fractions?