C# convert string to decimal 4dp - c#

I need to take a string object and convert it to a decimal to 4 dp.
So for example:
string val = "145.83011";
decimal sss = Math.Round(Convert.ToDecimal(val), 4);
bring back 145.8301 - good
However:
string val = "145.8300";
decimal sss = Math.Round(Convert.ToDecimal(val), 4);
brings back 145.83
I need it to be 145.8300
I need it in a decimal format so can't use string format options.
Thanks
rob

One option would be to use string manipulation three times:
Parse the original text to a decimal value (this will preserve the original number of decimal places)
Use string formatting to end up with a string with exactly 4 decimal places. (Math.Round ensures there are at most 4DP, but not exactly 4DP.)
Parse the result of the formatting to get back to a decimal value with exactly 4DP.
So something like this:
public static decimal Force4DecimalPlaces(string input)
{
decimal parsed = decimal.Parse(input, CultureInfo.InvariantCulture);
string intermediate = parsed.ToString("0.0000", CultureInfo.InvariantCulture);
return decimal.Parse(intermediate, CultureInfo.InvariantCulture);
}
I recoil from using string conversions like this, but the alternatives are relatively tricky. You could either get the raw bits, split out the different parts to find the mantissa and scale, then adjust appropriately... or you could potentially work out some sequence of arithmetic operations to get to the right scale. (Jeppe's approach of multiplying by 1.0000m may well be entirely correct - I just don't know whether it's documented to be correct. It would at least be worth adding in appropriate tests for the sorts of numbers you expect to see.)
Note that the above code will perform round up on halves, as far as I can tell, so 1.12345 will be converted to 1.1235 for example.
Sample with output in comments:
using System;
using System.Globalization;
class Test
{
static void Main()
{
Console.WriteLine(Force4DecimalPlaces("0.0000001")); // 0.0000
Console.WriteLine(Force4DecimalPlaces("1.000000")); // 1.0000
Console.WriteLine(Force4DecimalPlaces("1.5")); // 1.5000
Console.WriteLine(Force4DecimalPlaces("1.56789")); // 1.5679
}
public static decimal Force4DecimalPlaces(string input)
{
decimal parsed = decimal.Parse(input, CultureInfo.InvariantCulture);
string intermediate = parsed.ToString("0.0000", CultureInfo.InvariantCulture);
return decimal.Parse(intermediate, CultureInfo.InvariantCulture);
}
}

Both Convert.ToDecimal and decimal.Parse do preserve trailing zeroes in the string (a System.Decimal can have at most 28-29 digits in total, so in most cases there's still room for all the trailing zeroes).
And Math.Round(..., 4) preserves trailing zeroes up to the fourth place after the decimal period.
Therefore the premise of the question is wrong. Your example does bring back what you want.
In any case, consider specifying the overload that takes in an IFormatProvider as well, and give CultureInfo.InvariantCulture as argument. Then the conversion is independent of the local culture.
If instead you want to handle strings like "145.83" and append trailing zeroes that were not in the string, use:
string val = "145.83";
decimal sss = Math.Round(
decimal.Parse(val, CultureInfo.InvariantCulture) * 1.0000m,
4);
Epilog: If you don't like multiplying and dividing by numbers like 1.0000m, use decimal.GetBits to get the internal representation. Adjust the integer "part" by multiplying or dividing by the appropriate power of ten, and adjust the scale "part" by subtracting or adding the corresponding number. The scale counts the number of places to move the decimal point to the left, starting from the 96-bit integer.

Related

Converting Long String to Double in C#

I have the following code to convert a very long numeric string.
using System;
class MainClass {
public static void Main (string[] args) {
string longString = "1000000000000000000000000000001";
double convertedString = Double.Parse(test);
Console.WriteLine(test2);
}
}
However, convertedString is outputted in scientific notation:
1E+30
Is there a way to retain the exact value of the double when I convert it from a string?
The format of the output and the precision of the variable itself have nothing to do with each other. You can get the format you want by changing the format string, e.g.
Console.WriteLine("{0:N}", test1);
As for the precision of the variable, you should be aware that floating point numbers are not precise. And your number is about ten digits too long to fit into a long.
You will either need to store that number as a custom data type or, if it is just an identifier and not actually a number on which you need to perform math, simply store it as a string.

string format money , [duplicate]

I need to display a number with commas and a decimal point.
Eg:
Case 1 : Decimal number is 432324 (This does not have commas or decimal points).
Need to display it as: 432,324.00.
Not: 432,324
Case 2 : Decimal number is 2222222.22 (This does not have commas).
Need to display it as: 2,222,222.22
I tried ToString("#,##0.##"), but it is not formatting it correctly.
int number = 1234567890;
number.ToString("#,##0.00");
You will get the result 1,234,567,890.00.
Maybe you simply want the standard format string "N", as in
number.ToString("N")
It will use thousand separators, and a fixed number of fractional decimals. The symbol for thousands separators and the symbol for the decimal point depend on the format provider (typically CultureInfo) you use, as does the number of decimals (which will normally by 2, as you require).
If the format provider specifies a different number of decimals, and if you don't want to change the format provider, you can give the number of decimals after the N, as in .ToString("N2").
Edit: The sizes of the groups between the commas are governed by the
CultureInfo.CurrentCulture.NumberFormat.NumberGroupSizes
array, given that you don't specify a special format provider.
Try with
ToString("#,##0.00")
From MSDN
*The "0" custom format specifier serves as a zero-placeholder symbol. If the value that is being formatted has a digit in the position where the zero appears in the format string, that digit is copied to the result string; otherwise, a zero appears in the result string. The position of the leftmost zero before the decimal point and the rightmost zero after the decimal point determines the range of digits that are always present in the result string.
The "00" specifier causes the value to be rounded to the nearest digit preceding the decimal, where rounding away from zero is always used. For example, formatting 34.5 with "00" would result in the value 35.*
I had the same problem. I wanted to format numbers like the "General" format in spreadsheets, meaning show decimals if they're significant, but chop them off if not. In other words:
1234.56 => 1,234.56
1234 => 1,234
It needs to support a maximum number of places after the decimal, but don't put trailing zeros or dots if not required, and of course, it needs to be culture friendly. I never really figured out a clean way to do it using String.Format alone, but a combination of String.Format and Regex.Replace with some culture help from NumberFormatInfo.CurrentInfo did the job (LinqPad C# Program).
string FormatNumber<T>(T number, int maxDecimals = 4) {
return Regex.Replace(String.Format("{0:n" + maxDecimals + "}", number),
#"[" + System.Globalization.NumberFormatInfo.CurrentInfo.NumberDecimalSeparator + "]?0+$", "");
}
void Main(){
foreach (var test in new[] { 123, 1234, 1234.56, 123456.789, 1234.56789123 } )
Console.WriteLine(test + " = " + FormatNumber(test));
}
Produces:
123 = 123
1234 = 1,234
1234.56 = 1,234.56
123456.789 = 123,456.789
1234.56789123 = 1,234.5679
Try with
ToString("#,##0.###")
Produces:
1234.55678 => 1,234.556
1234 => 1,234
For Razor View:
$#string.Format("{0:#,0.00}",item.TotalAmount)
CultureInfo us = new CultureInfo("en-US");
TotalAmount.ToString("N", us)
Your question is not very clear but this should achieve what you are trying to do:
decimal numericValue = 3494309432324.00m;
string formatted = numericValue.ToString("#,##0.00");
Then formatted will contain: 3,494,309,432,324.00
All that is needed is "#,0.00", c# does the rest.
Num.ToString("#,0.00"")
The "#,0" formats the thousand separators
"0.00" forces two decimal points
If you are using string variables you can format the string directly using a : then specify the format (e.g. N0, P2, etc).
decimal Number = 2000.55512016465m;
$"{Number:N}" #Outputs 2,000.55512016465
You can also specify the number of decimal places to show by adding a number to the end like
$"{Number:N1}" #Outputs 2,000.5
$"{Number:N2}" #Outputs 2,000.55
$"{Number:N3}" #Outputs 2,000.555
$"{Number:N4}" #Outputs 2,000.5551
string Mynewcurrency = DisplayIndianCurrency("7743450.00");
private string DisplayIndianCurrency(string EXruppesformate)
{
string fare = EXruppesformate;
decimal parsed = decimal.Parse(fare, CultureInfo.InvariantCulture);
CultureInfo hindi = new CultureInfo("en-IN");
// string text = string.Format(hindi, "{0:c}", parsed);if you want <b>Rs 77,43,450.00</b>
string text = string.Format(hindi, "{0:N}", parsed); //if you want <b>77,43,450.00</b>
return ruppesformate = text;
}
For anyone looking at this now, and getting the "No overload for method 'ToString' takes 1 argument" when using:
TotalNumber.ToString("N")
My solution has been to use :
TotalNumber.Value.ToString("N")
I often get stuck on this when working directly inside an MVC View, the following wasn't working:
#Model.Sum(x => x.Number).ToString("N")
Whereas this works:
#Model.Sum(x => x.Number).Value.ToString("N")

C# - Using NumberFormatInfo with Convert.ToDouble to return double

In my application I have internationalization and so we have a bunch of methods to deal with formatting.
One of them should receive a double and format it to two decimal places and return a double. For doing so, we are using NumberFormatInfo according to the culture selected.
The problem is I cant get Convert.ToDouble to work with NumberFormatInfo the way I would like to. Basically what I want to know is why this:
using System;
using System.Globalization;
public class Program
{
public static void Main()
{
var myDouble = 9.983743;
var nfi = new NumberFormatInfo() {
NumberDecimalDigits = 2
};
Console.WriteLine("Original value: " + myDouble);
Console.WriteLine("Converted value: " + Convert.ToDouble(myDouble, nfi));
}
}
Prints
Original value: 9.983743
Converted value: 9.983743 // Should be 9.98
And how can I get the result I want using NumberFormatInfo only, if possible.
Thanks,
From MSDN:
The NumberDecimalDigits property is used with the "F" and "N" standard format strings without a precision specifier in numeric formatting operations.
The default is the generic formatting (G). So this will give you the desired result:
Console.WriteLine(myDouble.ToString("N", nfi));
However, 2 is the default value anyway. And it is better to specify it explicitly:
Console.WriteLine(myDouble.ToString("N2", NumberFormatInfo.InvariantInfo));
Update:
Yeah but I do need to return a double from my method.
Now I see. In your place I would return the original double in that case, too. If the consumer of your API wants to display/store it as a string with two digits, then it is his responsibility to format it.
If you really want to omit the last digits of the precision and return a modified value, then use Math.Round instead (but I would not recommend that).
Converting a double to a double does not change anything, a double is always double precision, you cannot change the number of decimal digits.
A double has no format, format comes into play when you display a double by using the ToString() method as explained by taffer.
You can round it down to set all digits after the first 2 to zero, but you cannot remove digits.
You state you want to return a double with only 2 digits after the decimal place. Therefore, you are not formatting you are rounding:
Math.Round(myDouble, 2)
9.98

Format decimal number with custom amount of digits after comma

I have this custom extension that should format a decimal number with a custom amount of digits after comma.
public static decimal FormatDecimal(this decimal value, int decimalSeparator = 2)
{
decimal returnValue = Math.Round(value, decimalSeparator, MidpointRounding.AwayFromZero);
return returnValue;
}
The problem is that doesn't work as expected.
If I do like this:
decimal number = 12345;
and then:
decimal formatedNumber = number.FormatDecimal(2);
the result should be:
12345.00
instead the result is:
12345
What I am doing wrong?
Here's the extension function working
public static string FormatDecimal(this decimal value, int decimalSeparator = 2)
{
return value.ToString(string.Format("0.{0}", new string('0', decimalSeparator)));
}
I think the right way is to using The "0" custom format specifier;
Replaces the zero with the corresponding digit if one is present;
otherwise, zero appears in the result string.
For example;
decimal d = 12345;
Console.WriteLine(d.ToString("#.00")); // 12345.00
You're probably looking to format the string representation of your decimal instead. Try this:
decimal myNumber = 12345.67m;
string formattedNumber = myNumber.ToString("N3");
Console.WriteLine(formattedNumber); // Prints "12345.670"
See here for more information: https://msdn.microsoft.com/en-us/library/dwhawy9k%28v=vs.110%29.aspx
From MSDN:
Standard numeric format strings are used to format common numeric types. A standard numeric format string takes the form Axx, where:
A is a single alphabetic character called the format specifier. Any numeric format string that contains more than one alphabetic character, including white space, is interpreted as a custom numeric format string. For more information, see Custom Numeric Format Strings.
xx is an optional integer called the precision specifier. The precision specifier ranges from 0 to 99 and affects the number of digits in the result. Note that the precision specifier controls the number of digits in the string representation of a number. It does not round the number itself. To perform a rounding operation, use the Math.Ceiling, Math.Floor, or Math.Round method.
When precision specifier controls the number of fractional digits in the result string, the result strings reflect numbers that are rounded away from zero (that is, using MidpointRounding.AwayFromZero).
You should specify the formatting when you display the string.
What you need is to do the following, when you convert to string:
String.Format("{0:0.00}", formatedNumber);
Refer to This article for more details:

How to convert decimal to money format

I'm trying to convert a number so it looks like the formatting in money.
I need to take 258000 and make it 2,580.00 or 25000 and make it 250.00 or 360 and make it 3.60
This is what I'm using but it's adding the ".00" at the end of all numbers making 2500 2500.00 but it should be 25.00.
Value = string.Format("{0:##,###.00}", Convert.ToDecimal(Value));
It seems to me that you're just missing the fact that you can divide the user's input by 100 after parsing it:
using System;
class Program
{
static void Main(string[] args)
{
string input = "2500";
decimal cents = decimal.Parse(input); // Potentially use TryParse...
decimal dollars = cents / 100m;
string output = dollars.ToString("0.00");
Console.WriteLine(output); // 25.00
}
}
Note that there are complicated cultural rules around how currency values should be displayed - I would suggest using the C format specifier, using a CultureInfo which is like whatever the users are expecting, but with the NumberFormatInfo.CurrencySymbol set to an empty string.
You should also consider which culture to use when parsing the user's input - it can significantly affect the results if they decide to use grouping separators or decimal separators. Will they always be entering an integer? If so, parse it as an integer too.
double valueOriginal = 260;
Response.Write( (valueOriginal / 100).ToString("C"));
260 = (206/100)
then
(260/100).ToString("C");

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