C#•2mo ago

Need an extension method to generate a random decimal within a range

Making post here cause I forgot to look at some of the answers given

50 Replies

Angius•2mo ago

.NextDouble() * upperBound...? Cast to a decimal

MangoOP•2mo ago

How to set min value?

Angius•2mo ago

random * (max - min) + min

MangoOP•2mo ago

random being the result of the previous code?

Angius•2mo ago

random being a random double Random.Shared.NextDouble() * (max - min) + min

cned•2mo ago

What do you mean by "random". Because converting between types is going to mess up precision, which is going to introduce some bias. A "random decimal" is a sort of odd concept.

MangoOP•2mo ago

I need a random value that is a decimal I need it to generate a random figure that can represent money

Cattywampus•2mo ago

you need to round it.. as in math.round I gave you already in #chat

MODiX•2mo ago

Cattywampus

REPL Result: Success

double a =  Math.Round((new Random().NextDouble() / 100), 3);
Console.WriteLine(a);

double a =  Math.Round((new Random().NextDouble() / 100), 3);
Console.WriteLine(a);

Console Output

0.002

0.002

Compile: 391.973ms | Execution: 73.928ms | React with ❌ to remove this embed.

MangoOP•2mo ago

I know, I forgot to save it

Cattywampus•2mo ago

thats rounding to exact decimal value

Yawnder•2mo ago

@A Certain Scientific Railgun Where does the "has to be an extension method" requirement comes from?

MangoOP•2mo ago

Doesn’t have to be, I’d like it to be

Yawnder•2mo ago

Ok. You want to extend what?

MangoOP•2mo ago

Random

Yawnder•2mo ago

Ok, so you want to use the same seed? Alright. Do you have a requirement that the random has to be "perfect", or just "quite good enough"?

MangoOP•2mo ago

Good enough It may be used for scientific data but will primarily be used for currency

Cattywampus•2mo ago

either you use the above I gave which is quite decent or if you want to get fancy, just use power 10 int then convert to bytes then convert back to decimal

Yawnder•2mo ago

public static decimal MyThing(this Random rnd, decimal lowerBound, decimalUpperBound)
{
// Guard for lower < upper
return (upperBound-lowerBound)*(decimal)rnd.NextDouble()+lowerBound;
}

public static decimal MyThing(this Random rnd, decimal lowerBound, decimalUpperBound)
{
// Guard for lower < upper
return (upperBound-lowerBound)*(decimal)rnd.NextDouble()+lowerBound;
}

Cattywampus•2mo ago

this will give double precision not decimal precision

MangoOP•2mo ago

Which part is precision?

MODiX•2mo ago

Mango

Good enough

Quoted by

<@163876962710847488> from #Need an extension method to generate a random decimal within a range (click here)

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MangoOP•2mo ago

The rounding?

Cattywampus•2mo ago

MangoOP•2mo ago

Yea I just need something that will give me something like "1.21m"

Yawnder•2mo ago

And it might not be perfectly distributed. Like you might get more or less chances of getting a number between 0.947259863249856 and 0.947259863249857 and you would between 0.4397747587 and 0.4397747588 (ignore the scale difference in my sarcastic message)

Cattywampus•2mo ago

thus you must round it 😌 the rounding must truncate the double precission

Yawnder•2mo ago

No. There is nothing in the requirements that talks about rounding. If "good enough" is the requirement, good enough is good enough.

MODiX•2mo ago

Cattywampus

REPL Result: Success

double a =  Math.Round((new Random().NextDouble() / 100), 3);
Console.WriteLine(a);

double a =  Math.Round((new Random().NextDouble() / 100), 3);
Console.WriteLine(a);

Console Output

0.01

0.01

Compile: 442.908ms | Execution: 33.696ms | React with ❌ to remove this embed.

Cattywampus•2mo ago

oh lord dont y'all see the difference like right in front y'all eyes aight time to sleep... it's 8 .50am now :HmmCouncilRTX3:

MangoOP•2mo ago

Fwiw, the rounding doesn’t have to be correct

MODiX•2mo ago

Yawnder

REPL Result: Failure

double a =  Math.Round((new Random().NextDouble() / (decimal)100), 3);
Console.WriteLine(a);

double a =  Math.Round((new Random().NextDouble() / (decimal)100), 3);
Console.WriteLine(a);

Exception: CompilationErrorException

- Operator '/' cannot be applied to operands of type 'double' and 'decimal'

- Operator '/' cannot be applied to operands of type 'double' and 'decimal'

Compile: 422.067ms | Execution: 0.000ms | React with ❌ to remove this embed.

MangoOP•2mo ago

I just want some random decimals between -300.00 and 300.00

MODiX•2mo ago

Yawnder

REPL Result: Success

double a =  Math.Round((new Random().NextDouble() / (double)100), 3);
Console.WriteLine(a);

double a =  Math.Round((new Random().NextDouble() / (double)100), 3);
Console.WriteLine(a);

Console Output

0.008

0.008

Compile: 437.504ms | Execution: 33.612ms | React with ❌ to remove this embed.

MangoOP•2mo ago

If it matters I plan to round to 2 decimal places But the rounding itself doesn’t need to be accurate This is to create mock data

Cattywampus•2mo ago

i mean, you wont get decimal precission anyway, thus the rounding is iimportant

Yawnder•2mo ago

You could be lazy then... rnd.Next(-30000M,30000M)/100M Anyhow, gtg. You already have many ways to skin the cat.

Cattywampus•2mo ago

incase y'all missing the point here

Cattywampus•2mo ago

https://learn.microsoft.com/en-us/dotnet/api/system.math.round?view=net-9.0 time to sleep now 🤤

MangoOP•2mo ago

I need a decimal. Not feline pelts

MangoOP•2mo ago

https://tenor.com/view/bigdecimal-java-gif-26673276

Tenor

MangoOP•2mo ago

Also Is there a format for decimal to format it to currency where negative is -$1,234.56 and not ($1,234.56)? My end users are electrical engineers, not boring accountants like @viceroypenguin | 🦋🐧

ero•2mo ago

You have your answer, no? $close

MODiX•2mo ago

If you have no further questions, please use /close to mark the forum thread as answered

MangoOP•2mo ago

$close

MODiX•2mo ago

If you have no further questions, please use /close to mark the forum thread as answered

ero•2mo ago

i posted an answer to this in #chat when you asked it, check your inbox (hope it's there)

MODiX•2mo ago

ero

REPL Result: Success

static decimal NextDecimal(this Random random, decimal lowerInclusive, decimal upperExclusive)
{
  return (decimal)Random.Shared.NextDouble() * (upperExclusive - lowerInclusive) + lowerInclusive;
}

var culture = (CultureInfo)CultureInfo.GetCultureInfo("en-US").Clone();
culture.NumberFormat.CurrencyNegativePattern = 1;

var value = Random.Shared.NextDecimal(-300, 0);
value.ToString("C", culture)

static decimal NextDecimal(this Random random, decimal lowerInclusive, decimal upperExclusive)
{
  return (decimal)Random.Shared.NextDouble() * (upperExclusive - lowerInclusive) + lowerInclusive;
}

var culture = (CultureInfo)CultureInfo.GetCultureInfo("en-US").Clone();
culture.NumberFormat.CurrencyNegativePattern = 1;

var value = Random.Shared.NextDecimal(-300, 0);
value.ToString("C", culture)

Result: string

-$249.96

-$249.96

Compile: 437.786ms | Execution: 36.119ms | React with ❌ to remove this embed.

ero•2mo ago

@A Certain Scientific Railgun

Cattywampus•2mo ago

👍

Gaming

Programming

Need an extension method to generate a random decimal within a range

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