Numeric ("N") Format Specifier In C#

Introduction

The numeric format specifier "N" converts a number to a string format as "-d,ddd,ddd.ddd…" where the "-" sign denotes the negative number symbol, "," denotes a separator between these groups, "d" denotes any number (0-9), and "." represents the decimal point in the number. For this, we use the properties of the NumberFormatInfo class. First of all, the following example shows how we convert the number into the string format.

namespace NumericFunction
{
    class Program
    {
        static void Main(string[] args)
        {
            //define a double type number
            double number = -98765.6789;

            //convert double number into a string
            Console.WriteLine(" The double group number is:"+number.ToString("N", CultureInfo.InvariantCulture));

            //define the integer type number
            int intValue = 123456789;

            //convert integer number into the string
            Console.WriteLine("The integer grouped number is :"+intValue.ToString("N1", CultureInfo.InvariantCulture));           
        }
    }
}

Output

The various properties with their examples are as follows.

NumberNegativePattern

This property is used to define the format of negative values and specifies whether the negative sign is represented by parentheses or the NegativeSign property, or we can say that it gets or sets the format pattern for negative numeric values. This property has one of the following values.

Value	Pattern
0	(n)
1	-n
2	- n
3	n-
4	n -

Here, n denotes the number, and "-" denotes the negative sign. For example.

namespace NumericFunction
{
    class Program
    {
        static void Main(string[] args)
        {
            // Creates a object of NumberFormatinfo class
            NumberFormatInfo number = new NumberFormatInfo();

            // Initialize a negative value.
            Int64 myInt = -1234;

            // The default formatting of the number is displayed here
            Console.WriteLine("Default Formatting of the Number is as \t:\t{0}", myInt.ToString("N", number));

            // Displays the value with other patterns.
            for (int i = 0; i <= 4; i++)
            {
                number.NumberNegativePattern = i;
                Console.WriteLine("New Pattern with value {0}\t:\t{1}", number.NumberNegativePattern, myInt.ToString("N", number));

            }         
        }
    }
}

Output

NumberGroupSizes

This property defines the number of integral digits that appear between group separators. We can also say that it gets or sets the number of digits in each group to the left of the decimal in numeric values. For example.

namespace NumericFunction
{
    class Program
    {
        static void Main(string[] args)
        {
            // Gets a NumberFormatInfo associated with the en-US culture.
            NumberFormatInfo nfi = new CultureInfo("en-US", false).NumberFormat;

            // Intialize a integer value
            Int64 number = 123456789012345;

            //Display the default numeric value
            Console.WriteLine("Default Number is as :"+number.ToString("N", nfi));

            // Displays the same value with different groupings.

            //sizes1 denotes an array has sizes 2,3 and 4
            int[] Sizes1 = { 2, 3, 4 };

            //sizes2 denotes an array has sizes 2,3 and 0
            int[] Sizes2 = { 2, 3, 0 };

            nfi.NumberGroupSizes = Sizes1;
            Console.WriteLine("After apply size 1 In number Format :"+number.ToString("N", nfi));
            nfi.NumberGroupSizes = Sizes2;
            Console.WriteLine("After apply the size 2 In number format :"+number.ToString("N", nfi));       
        }
    }
}

Here, Size1 applies 2, 3, and 4 sizes to the number. In other words, now the grouping begins from the right side of the number after the decimal point, and the first two digits will be grouped, then 3 digits, then 4 digits; after that, if digits are left, all are grouped by 4 digit numbers, the same as Size2.

Output

NumberGroupSeparator

This property is used to separate the number by grouping. In other words, if the number is grouped (apply comma in this) then this property separates a number where the comma exists, or we can say that it gets or sets the string that separates groups of digits to the left of the decimal in numeric values, for example.

namespace NumericFunction
{
    class Program
    {
        static void Main(string[] args)
        {
            // Gets a NumberFormatInfo with the en-US culture.
            NumberFormatInfo nfi = new CultureInfo("en-US", false).NumberFormat;

            // Displays a value with the default separator (",").
            Int64 myInt = 123456789;

            Console.WriteLine("Grouped Value : "+myInt.ToString("N", nfi));
            // Displays the same value when apply separator.

            nfi.NumberGroupSeparator = " ";
            Console.WriteLine("Seperated Value :"+myInt.ToString("N", nfi));  
        }
    }
}

Output

NumberDecimalSeparator

This property will separate the number after the decimal point from the number that exists before the decimal point. Or we can say that it gets or sets the string to use as the decimal separator in numeric values, for example.

namespace NumericFunction
{
    class Program
    {
        static void Main(string[] args)
        {
            // Gets a NumberFormatInfo with the en-US culture.
            NumberFormatInfo nfi = new CultureInfo("en-US", false).NumberFormat;

            // Displays a value with the default separator (",").
            Int64 myInt = 123456789;
            Console.WriteLine("Grouped Value : "+myInt.ToString("N", nfi));

            // Displays the same value when apply decimal separator.
            nfi.NumberDecimalSeparator = " ";
            Console.WriteLine("Decimal Seperated Value :"+myInt.ToString("N", nfi));  
        }
    }
}

Output

NumberDecimalDigit

This property is used to get and set the number of decimal places in the grouped number format, for example.

namespace NumericFunction
{
    class Program
    {
        static void Main(string[] args)
        {
            // Gets a NumberFormatInfo with the en-US culture.
            NumberFormatInfo nfi = new CultureInfo("en-US", false).NumberFormat;

            // Displays a value with the default separator (",").
            Int64 myInt = 123456789;
            Console.WriteLine("Grouped Value : "+myInt.ToString("N", nfi));

            // Displays the same value when apply number decimal digits
            nfi.NumberDecimalDigits = 5;
            Console.WriteLine("Number Decimal Value :"+myInt.ToString("N", nfi));  
        }
    }
}

Output

Summary

In this article, I explained how to use the number format specifier to perform various changes in the number format string in C#.