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Standard Numeric Format Strings

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Updated: October 2010

Standard numeric format strings are used to format common numeric types. A standard numeric format string takes the form Axx, where A is an alphabetic character called the format specifier, and 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. 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.

Standard numeric format strings are supported by some overloads of the ToString method of all numeric types. For example, you can supply a numeric format string to the ToString(String) and ToString(String, IFormatProvider) methods of the Int32 type. Standard numeric format strings are also supported by the .NET Framework composite formatting feature, which is used by some Write and WriteLine methods of the Console and StreamWriter classes, the String.Format method, and the StringBuilder.AppendFormat method.

The following table describes the standard numeric format specifiers and displays sample output produced by each format specifier. See the Notes section for additional information about using standard numeric format strings, and the Example section for a comprehensive illustration of their use.

Format specifier

Name

Description

Examples

"C" or "c"

Currency

Result: A currency value.

Supported by: All numeric types.

Precision specifier: Number of decimal digits.

Default precision specifier: Defined by System.Globalization.NumberFormatInfo.

More information: The Currency ("C") Format Specifier.

123.456 ("C", en-US) -> $123.46

123.456 ("C", fr-FR) -> 123,46 €

123.456 ("C", ja-JP) -> ¥123

-123.456 ("C3", en-US) -> ($123.456)

-123.456 ("C3", fr-FR) -> -123,456 €

-123.456 ("C3", ja-JP) -> -¥123.456

"D" or "d"

Decimal

Result: Integer digits with optional negative sign.

Supported by: Integral types only.

Precision specifier: Minimum number of digits.

Default precision specifier: Minimum number of digits required.

More information: The Decimal("D") Format Specifier.

1234 ("D") -> 1234

-1234 ("D6") -> -001234

"E" or "e"

Exponential (scientific)

Result: Exponential notation.

Supported by: All numeric types.

Precision specifier: Number of decimal digits.

Default precision specifier: 6.

More information: The Exponential ("E") Format Specifier.

1052.0329112756 ("E", en-US) -> 1.052033E+003

1052.0329112756 ("e", fr-FR) -> 1,052033e+003

-1052.0329112756 ("e2", en-US) -> -1.05e+003

-1052.0329112756 ("E2", fr_FR) -> -1,05E+003

"F" or "f"

Fixed-point

Result: Integral and decimal digits with optional negative sign.

Supported by: All numeric types.

Precision specifier: Number of decimal digits.

Default precision specifier: Defined by System.Globalization.NumberFormatInfo.

More information: The Fixed-Point ("F") Format Specifier.

1234.567 ("F", en-US) -> 1234.57

1234.567 ("F", de-DE) -> 1234,57

1234 ("F1", en-US) -> 1234.0

1234 ("F1", de-DE) -> 1234,0

-1234.56 ("F4", en-US) -> -1234.5600

-1234.56 ("F4", de-DE) -> -1234,5600

"G" or "g"

General

Result: The most compact of either fixed-point or scientific notation.

Supported by: All numeric types.

Precision specifier: Number of significant digits.

Default precision specifier: Depends on numeric type.

More information: The General ("G") Format Specifier.

-123.456 ("G", en-US) -> -123.456

123.456 ("G", sv-SE) -> -123,456

123.4546 ("G4", en-US) -> 123.5

123.4546 ("G4", sv-SE) -> 123,5

-1.234567890e-25 ("G", en-US) -> -1.23456789E-25

-1.234567890e-25 ("G", sv-SE) -> -1,23456789E-25

"N" or "n"

Number

Result: Integral and decimal digits, group separators, and a decimal separator with optional negative sign.

Supported by: All numeric types.

Precision specifier: Desired number of decimal places.

Default precision specifier: Defined by System.Globalization.NumberFormatInfo.

More information: The Numeric ("N") Format Specifier.

1234.567 ("N", en-US) -> 1,234.57

1234.567 ("N", ru-RU) -> 1 234,57

1234 ("N", en-US) -> 1,234.0

1234 ("N", ru-RU) -> 1 234,0

-1234.56 ("N", en-US) -> -1,234.560

-1234.56 ("N", ru-RU) -> -1 234,560

"P" or "p"

Percent

Result: Number multiplied by 100 and displayed with a percent symbol.

Supported by: All numeric types.

Precision specifier: Desired number of decimal places.

Default precision specifier: Defined by System.Globalization.NumberFormatInfo.

More information: The Percent ("P") Format Specifier.

1 ("P", en-US) -> 100.00 %

1 ("P", fr-FR) -> 100,00 %

-0.39678 ("P1", en-US) -> -39.7 %

-0.39678 ("P1", fr-FR) -> -39,7 %

"R" or "r"

Round-trip

Result: A string that can round-trip to an identical number.

Supported by: Single and Double.

Precision specifier: Ignored.

More information: The Round-trip ("R") Format Specifier.

123456789.12345678 ("R") -> 123456789.12345678

-1234567890.12345678 ("R") -> -1234567890.1234567

"X" or "x"

Hexadecimal

Result: A hexadecimal string.

Supported by: Integral types only.

Precision specifier: Number of digits in the result string.

More information: The HexaDecimal ("X") Format Specifier.

255 ("X") -> FF

-1 ("x") -> ff

255 ("x4") -> 00ff

-1 ("X4") -> 00FF

Any other single character

Unknown specifier

Result: Throws a FormatException at run time.

Using Standard Numeric Format Strings

A standard numeric format string can be used to define the formatting of a numeric value in one of two ways:

  • It can be passed to an overload of the ToString method that has a format parameter. The following example formats a numeric value as a currency string in the current (in this case, the en-US) culture.

  • It can be supplied as the formatString parameter in a format item used with such methods as String.Format, Console.WriteLine, and StringBuilder.AppendFormat. For more information, see Composite Formatting. The following example uses a format item to insert a currency value in a string.

The following sections provide detailed information about each of the standard numeric format strings.

The Currency ("C") Format Specifier

The "C" (or currency) format specifier converts a number to a string that represents a currency amount. The precision specifier indicates the desired number of decimal places in the result string. If the precision specifier is omitted, the default precision is defined by the NumberFormatInfo.CurrencyDecimalDigits property.

If the value to be formatted has more than the specified or default number of decimal places, the fractional value is rounded in the result string. If the value to the right of the number of specified decimal places is 5 or greater, the last digit in the result string is rounded away from zero.

The result string is affected by the formatting information of the current NumberFormatInfo object. The following table lists the NumberFormatInfo properties that control the formatting of the returned string.

NumberFormatInfo property

Description

CurrencyPositivePattern

Defines the placement of the currency symbol for positive values.

CurrencyNegativePattern

Defines the placement of the currency symbol for negative values, and specifies whether the negative sign is represented by parentheses or the NegativeSign property.

NegativeSign

Defines the negative sign used if CurrencyNegativePattern indicates that parentheses are not used.

CurrencySymbol

Defines the currency symbol.

CurrencyDecimalDigits

Defines the default number of decimal digits in a currency value. This value can be overridden by using the precision specifier.

CurrencyDecimalSeparator

Defines the string that separates integral and decimal digits.

CurrencyGroupSeparator

Defines the string that separates groups of integral numbers.

CurrencyGroupSizes

Defines the number of integer digits that appear in a group.

The following example formats a Double value with the currency format specifier.

Dim value As Double = 12345.6789
outputBlock.Text &= String.Format(value.ToString("C", CultureInfo.InvariantCulture)) & vbCrLf
' Displays ☼12,345.68 

outputBlock.Text &= String.Format(value.ToString("C3", CultureInfo.InvariantCulture)) & vbCrLf
' Displays ☼12,345.679

outputBlock.Text &= value.ToString("C3", _
                  New CultureInfo("en-US")) & vbCrLf
' Displays $12,345.679

double value = 12345.6789;
outputBlock.Text += value.ToString("C", CultureInfo.InvariantCulture) + "\n";
// Displays ☼12,345.68 

outputBlock.Text += value.ToString("C3", CultureInfo.InvariantCulture) + "\n";
// Displays ☼12,345.679

outputBlock.Text += value.ToString("C3", new CultureInfo("en-US")) + "\n";
// Displays $12,345.679

Back to table

The Decimal ("D") Format Specifier

The "D" (or decimal) format specifier converts a number to a string of decimal digits (0-9), prefixed by a minus sign if the number is negative. This format is supported only for integral types.

The precision specifier indicates the minimum number of digits desired in the resulting string. If required, the number is padded with zeros to its left to produce the number of digits given by the precision specifier. If no precision specifier is specified, the default is the minimum value required to represent the integer without leading zeros.

The result string is affected by the formatting information of the current NumberFormatInfo object. As the following table shows, a single property affects the formatting of the result string.

NumberFormatInfo property

Description

NegativeSign

Defines the string that indicates that a number is negative.

The following example formats an Int32 value with the decimal format specifier.

Dim value As Integer

value = 12345
outputBlock.Text &= value.ToString("D") & vbCrLf
' Displays 12345   
outputBlock.Text &= value.ToString("D8") & vbCrLf
' Displays 00012345

value = -12345
outputBlock.Text &= value.ToString("D") & vbCrLf
' Displays -12345
outputBlock.Text &= value.ToString("D8") & vbCrLf
' Displays -00012345

int value;

value = 12345;
outputBlock.Text += value.ToString("D") + "\n";
// Displays 12345
outputBlock.Text += value.ToString("D8") + "\n";
// Displays 00012345

value = -12345;
outputBlock.Text += value.ToString("D") + "\n";
// Displays -12345
outputBlock.Text += value.ToString("D8") + "\n";
// Displays -00012345

Back to table

The Exponential ("E") Format Specifier

The exponential ("E") format specifier converts a number to a string of the form "-d.ddd…E+ddd" or "-d.ddd…e+ddd", where each "d" indicates a digit (0-9). The string starts with a minus sign if the number is negative. One digit always precedes the decimal point.

The precision specifier indicates the desired number of digits after the decimal point. If the precision specifier is omitted, a default of six digits after the decimal point is used.

The case of the format specifier indicates whether to prefix the exponent with an "E" or an "e". The exponent always consists of a plus or minus sign and a minimum of three digits. The exponent is padded with zeros to meet this minimum, if required.

The result string is affected by the formatting information of the current NumberFormatInfo object. The following table lists the NumberFormatInfo properties that control the formatting of the returned string.

NumberFormatInfo property

Description

NegativeSign

Defines the string that indicates that a number is negative for both the coefficient and exponent.

NumberDecimalSeparator

Defines the string that separates the integral digit from decimal digits in the coefficient.

PositiveSign

Defines the string that indicates that an exponent is positive.

The following example formats a Double value with the exponential format specifier.

Dim value As Double = 12345.6789
outputBlock.Text &= String.Format(value.ToString("E", CultureInfo.InvariantCulture)) & vbCrLf
' Displays 1.234568E+004

outputBlock.Text &= String.Format(value.ToString("E10", CultureInfo.InvariantCulture)) & vbCrLf
' Displays 1.2345678900E+004

outputBlock.Text &= String.Format(value.ToString("e4", CultureInfo.InvariantCulture)) & vbCrLf
' Displays 1.2346e+004

outputBlock.Text &= value.ToString("E", _
                  New CultureInfo("fr-FR")) & vbCrLf
' Displays 1,234568E+004

double value = 12345.6789;
outputBlock.Text += value.ToString("E", CultureInfo.InvariantCulture) + "\n";
// Displays 1.234568E+004

outputBlock.Text += value.ToString("E10", CultureInfo.InvariantCulture) + "\n";
// Displays 1.2345678900E+004

outputBlock.Text += value.ToString("e4", CultureInfo.InvariantCulture) + "\n";
// Displays 1.2346e+004

outputBlock.Text += value.ToString("E", new CultureInfo("fr-FR")) + "\n";
// Displays 1,234568E+004

Back to table

The Fixed-Point ("F") Format Specifier

The fixed-point ("F) format specifier converts a number to a string of the form "-ddd.ddd…" where each "d" indicates a digit (0-9). The string starts with a minus sign if the number is negative.

The precision specifier indicates the desired number of decimal places. If the precision specifier is omitted, the current NumberFormatInfo.NumberDecimalDigits property supplies the numeric precision.

The result string is affected by the formatting information of the current NumberFormatInfo object. The following table lists the properties of the NumberFormatInfo object that control the formatting of the result string.

NumberFormatInfo property

Description

NegativeSign

Defines the string that indicates that a number is negative.

NumberDecimalSeparator

Defines the string that separates integral digits from decimal digits.

NumberDecimalDigits

Defines the default number of decimal digits. This value can be overridden by using the precision specifier.

The following example formats a Double and an Int32 value with the fixed-point format specifier.

Dim integerNumber As Integer
integerNumber = 17843
outputBlock.Text &= String.Format(integerNumber.ToString("F", CultureInfo.InvariantCulture)) & vbCrLf
' Displays 17843.00

integerNumber = -29541
outputBlock.Text &= String.Format(integerNumber.ToString("F3", CultureInfo.InvariantCulture)) & vbCrLf
' Displays -29541.000

Dim doubleNumber As Double
doubleNumber = 18934.1879
outputBlock.Text &= String.Format(doubleNumber.ToString("F", CultureInfo.InvariantCulture)) & vbCrLf
' Displays 18934.19

outputBlock.Text &= String.Format(doubleNumber.ToString("F0", CultureInfo.InvariantCulture)) & vbCrLf
' Displays 18934

doubleNumber = -1898300.1987
outputBlock.Text &= String.Format(doubleNumber.ToString("F1", CultureInfo.InvariantCulture)) & vbCrLf
' Displays -1898300.2

outputBlock.Text &= doubleNumber.ToString("F3", _
                  New CultureInfo("es-ES")) & vbCrLf
' Displays -1898300,199                        

int integerNumber;
integerNumber = 17843;
outputBlock.Text += integerNumber.ToString("F",
                                           CultureInfo.InvariantCulture) + "\n";
// Displays 17843.00

integerNumber = -29541;
outputBlock.Text += integerNumber.ToString("F3",
                  CultureInfo.InvariantCulture) + "\n";
// Displays -29541.000

double doubleNumber;
doubleNumber = 18934.1879;
outputBlock.Text += doubleNumber.ToString("F", CultureInfo.InvariantCulture) + "\n";
// Displays 18934.19

outputBlock.Text += doubleNumber.ToString("F0", CultureInfo.InvariantCulture) + "\n";
// Displays 18934

doubleNumber = -1898300.1987;
outputBlock.Text += doubleNumber.ToString("F1", CultureInfo.InvariantCulture) + "\n";
// Displays -1898300.2

outputBlock.Text += doubleNumber.ToString("F3", new CultureInfo("es-ES")) + "\n";
// Displays -1898300,199

Back to table

The General ("G") Format Specifier

The general ("G") format specifier converts a number to the most compact of either fixed-point or scientific notation, depending on the type of the number and whether a precision specifier is present. The precision specifier defines the maximum number of significant digits that can appear in the result string. If the precision specifier is omitted or zero, the type of the number determines the default precision, as indicated in the following table.

Numeric type

Default precision

Byte or SByte

3 digits

Int16 or UInt16

5 digits

Int32 or UInt32

10 digits

Int64

19 digits

UInt64

20 digits

BigInteger

50 digits

Single

7 digits

Double

15 digits

Decimal

29 digits

Fixed-point notation is used if the exponent that would result from expressing the number in scientific notation is greater than -5 and less than the precision specifier; otherwise, scientific notation is used. The result contains a decimal point if required, and trailing zeros are omitted. If the precision specifier is present and the number of significant digits in the result exceeds the specified precision, the excess trailing digits are removed by rounding.

However, if the number is a Decimal and the precision specifier is omitted, fixed-point notation is always used and trailing zeros are preserved.

If scientific notation is used, the exponent in the result is prefixed with "E" if the format specifier is "G", or "e" if the format specifier is "g". The exponent contains a minimum of two digits. This differs from the format for scientific notation that is produced by the exponential format specifier, which includes a minimum of three digits in the exponent.

The result string is affected by the formatting information of the current NumberFormatInfo object. The following table lists the NumberFormatInfo properties that control the formatting of the result string.

NumberFormatInfo property

Description

NegativeSign

Defines the string that indicates that a number is negative.

NumberDecimalSeparator

Defines the string that separates integral digits from decimal digits.

NumberDecimalDigits

Defines the default number of decimal digits. This value can be overridden by using the precision specifier.

PositiveSign

Defines the string that indicates that an exponent is positive.

The following example formats assorted floating-point values with the general format specifier.

Dim number As Double

number = 12345.6789
outputBlock.Text &= String.Format(number.ToString("G", CultureInfo.InvariantCulture)) & vbCrLf
' Displays  12345.6789
outputBlock.Text &= number.ToString("G", _
                  New CultureInfo("fr-FR")) & vbCrLf
' Displays 12345,6789

outputBlock.Text &= String.Format(number.ToString("G7", CultureInfo.InvariantCulture)) & vbCrLf
' Displays 12345.68 

number = 0.0000023
outputBlock.Text &= String.Format(number.ToString("G", CultureInfo.InvariantCulture)) & vbCrLf
' Displays 2.3E-06       
outputBlock.Text &= number.ToString("G", _
                  New CultureInfo("fr-FR")) & vbCrLf
' Displays 2,3E-06

number = 0.0023
outputBlock.Text &= String.Format(number.ToString("G", CultureInfo.InvariantCulture)) & vbCrLf
' Displays 0.0023

number = 1234
outputBlock.Text &= String.Format(number.ToString("G2", CultureInfo.InvariantCulture)) & vbCrLf
' Displays 1.2E+03

number = Math.PI
outputBlock.Text &= String.Format(number.ToString("G5", CultureInfo.InvariantCulture)) & vbCrLf
' Displays 3.1416    

double number;

number = 12345.6789;
outputBlock.Text += number.ToString("G", CultureInfo.InvariantCulture) + "\n";
// Displays  12345.6789
outputBlock.Text += number.ToString("G", new CultureInfo("fr-FR")) + "\n";
// Displays 12345,6789

outputBlock.Text += number.ToString("G7", CultureInfo.InvariantCulture) + "\n";
// Displays 12345.68 

number = .0000023;
outputBlock.Text += number.ToString("G", CultureInfo.InvariantCulture) + "\n";
// Displays 2.3E-06       
outputBlock.Text += number.ToString("G", new CultureInfo("fr-FR")) + "\n";
// Displays 2,3E-06

number = .0023;
outputBlock.Text += number.ToString("G", CultureInfo.InvariantCulture) + "\n";
// Displays 0.0023

number = 1234;
outputBlock.Text += number.ToString("G2", CultureInfo.InvariantCulture) + "\n";
// Displays 1.2E+03

number = Math.PI;
outputBlock.Text += number.ToString("G5", CultureInfo.InvariantCulture) + "\n";
// Displays 3.1416

Back to table

The Numeric ("N") Format Specifier

The numeric ("N") format specifier converts a number to a string of the form "-d,ddd,ddd.ddd…", where "-" indicates a negative number symbol if required, "d" indicates a digit (0-9), "," indicates a group separator, and "." indicates a decimal point symbol. The precision specifier indicates the desired number of digits after the decimal point. If the precision specifier is omitted, the number of decimal places is defined by the current NumberFormatInfo.NumberDecimalDigits property.

The result string is affected by the formatting information of the current NumberFormatInfo object. The following table lists the NumberFormatInfo properties that control the formatting of the result string.

NumberFormatInfo property

Description

NegativeSign

Defines the string that indicates that a number is negative.

NumberNegativePattern

Defines the format of negative values, and specifies whether the negative sign is represented by parentheses or the NegativeSign property.

NumberGroupSizes

Defines the number of integral digits that appear between group separators.

NumberGroupSeparator

Defines the string that separates groups of integral numbers.

NumberDecimalSeparator

Defines the string that separates integral and decimal digits.

NumberDecimalDigits

Defines the default number of decimal digits. This value can be overridden by using a precision specifier.

The following example formats assorted floating-point values with the number format specifier.

Dim dblValue As Double = -12445.6789
outputBlock.Text &= String.Format(dblValue.ToString("N", CultureInfo.InvariantCulture)) & vbCrLf
' Displays -12,445.68
outputBlock.Text &= dblValue.ToString("N1", _
                  New CultureInfo("sv-SE")) & vbCrLf
' Displays -12 445,7

Dim intValue As Integer = 123456789
outputBlock.Text &= String.Format(intValue.ToString("N1", CultureInfo.InvariantCulture)) & vbCrLf
' Displays 123,456,789.0 

double dblValue = -12445.6789;
outputBlock.Text += dblValue.ToString("N", CultureInfo.InvariantCulture) + "\n";
// Displays -12,445.68
outputBlock.Text += dblValue.ToString("N1", new CultureInfo("sv-SE")) + "\n";
// Displays -12 445,7

int intValue = 123456789;
outputBlock.Text += intValue.ToString("N1", CultureInfo.InvariantCulture) + "\n";
// Displays 123,456,789.0

Back to table

The Percent ("P") Format Specifier

The percent ("P") format specifier multiplies a number by 100 and converts it to a string that represents a percentage. The precision specifier indicates the desired number of decimal places. If the precision specifier is omitted, the default numeric precision supplied by the current PercentDecimalDigits property is used.

The following table lists the NumberFormatInfo properties that control the formatting of the returned string.

NumberFormatInfo property

Description

PercentPositivePattern

Defines the placement of the percent symbol for positive values.

PercentNegativePattern

Defines the placement of the percent symbol and the negative symbol for negative values.

NegativeSign

Defines the string that indicates that a number is negative.

PercentSymbol

Defines the percent symbol.

PercentDecimalDigits

Defines the default number of decimal digits in a percentage value. This value can be overridden by using the precision specifier.

PercentDecimalSeparator

Defines the string that separates integral and decimal digits.

PercentGroupSeparator

Defines the string that separates groups of integral numbers.

PercentGroupSizes

Defines the number of integer digits that appear in a group.

The following example formats floating-point values with the percent format specifier.

Dim number As Double = 0.2468013
outputBlock.Text &= String.Format(number.ToString("P", CultureInfo.InvariantCulture)) & vbCrLf
' Displays 24.68 %
outputBlock.Text &= number.ToString("P", _
                  New CultureInfo("hr-HR")) & vbCrLf
' Displays 24,68%     
outputBlock.Text &= String.Format(number.ToString("P1", CultureInfo.InvariantCulture)) & vbCrLf
' Displays 24.7 %

double number = .2468013;
outputBlock.Text += number.ToString("P", CultureInfo.InvariantCulture) + "\n";
// Displays 24.68 %
outputBlock.Text += number.ToString("P", new CultureInfo("hr-HR")) + "\n";
// Displays 24,68%     
outputBlock.Text += number.ToString("P1", CultureInfo.InvariantCulture) + "\n";
// Displays 24.7 %

Back to table

The Round-trip ("R") Format Specifier

The round-trip ("R") format specifier guarantees that a numeric value that is converted to a string will be parsed back into the same numeric value. This format is supported only for the Single and Double types.

When a Single or Double value is formatted using this specifier, it is first tested using the general format, with 15 digits of precision for a Double and 7 digits of precision for a Single. If the value is successfully parsed back to the same numeric value, it is formatted using the general format specifier. If the value is not successfully parsed back to the same numeric value, it is formatted using 17 digits of precision for a Double and 9 digits of precision for a Single.

Although you can include a precision specifier, it is ignored. Round trips are given precedence over precision when using this specifier.

The result string is affected by the formatting information of the current NumberFormatInfo object. The following table lists the NumberFormatInfo properties that control the formatting of the result string.

NumberFormatInfo property

Description

NegativeSign

Defines the string that indicates that a number is negative.

NumberDecimalSeparator

Defines the string that separates integral digits from decimal digits.

PositiveSign

Defines the string that indicates that an exponent is positive.

The following example formats Double values with the round-trip format specifier.

Dim value As Double

value = Math.PI
outputBlock.Text &= value.ToString("r") & vbCrLf
' Displays 3.1415926535897931
outputBlock.Text &= value.ToString("r", _
                  New CultureInfo("fr-FR")) & vbCrLf
' Displays 3,1415926535897931
value = 1.623E-21
outputBlock.Text &= value.ToString("r") & vbCrLf
' Displays 1.623E-21

double value;

value = Math.PI;
outputBlock.Text += value.ToString("r") + "\n";
// Displays 3.1415926535897931
outputBlock.Text += value.ToString("r", new CultureInfo("fr-FR")) + "\n";
// Displays 3,1415926535897931
value = 1.623e-21;
outputBlock.Text += value.ToString("r") + "\n";
// Displays 1.623E-21

Back to table

The Hexadecimal ("X") Format Specifier

The hexadecimal ("X") format specifier converts a number to a string of hexadecimal digits. The case of the format specifier indicates whether to use uppercase or lowercase characters for hexadecimal digits that are greater than 9. For example, use "X" to produce "ABCDEF", and "x" to produce "abcdef". This format is supported only for integral types.

The precision specifier indicates the minimum number of digits desired in the resulting string. If required, the number is padded with zeros to its left to produce the number of digits given by the precision specifier.

The result string is not affected by the formatting information of the current NumberFormatInfo object.

The following example formats Int32 values with the hexadecimal format specifier.

Dim value As Integer

value = &H2045E
outputBlock.Text &= value.ToString("x") & vbCrLf
' Displays 2045e
outputBlock.Text &= value.ToString("X") & vbCrLf
' Displays 2045E
outputBlock.Text &= value.ToString("X8") & vbCrLf
' Displays 0002045E

value = 123456789
outputBlock.Text &= value.ToString("X") & vbCrLf
' Displays 75BCD15
outputBlock.Text &= value.ToString("X2") & vbCrLf
' Displays 75BCD15

int value;

value = 0x2045e;
outputBlock.Text += value.ToString("x") + "\n";
// Displays 2045e
outputBlock.Text += value.ToString("X") + "\n";
// Displays 2045E
outputBlock.Text += value.ToString("X8") + "\n";
// Displays 0002045E

value = 123456789;
outputBlock.Text += value.ToString("X") + "\n";
// Displays 75BCD15
outputBlock.Text += value.ToString("X2") + "\n";
// Displays 75BCD15

Back to table

Notes

Control Panel Settings

The settings in the Regional and Language Options item in Control Panel influence the result string produced by a formatting operation. Those settings are used to initialize the NumberFormatInfo object associated with the current thread culture, which provides values used to govern formatting. Computers that use different settings generate different result strings.

In addition, if the CultureInfo.CultureInfo(String) constructor is used to instantiate a new CultureInfo object that represents the same culture as the current system culture, any user customizations are reflected in the new CultureInfo object. You can use the CultureInfo.CreateSpecificCulture method to create a CultureInfo that does not reflect a system's customizations.

NumberFormatInfo Properties

Formatting is influenced by the properties of the current NumberFormatInfo object, which is provided implicitly by the current thread culture or explicitly by the IFormatProvider parameter of the method that invokes formatting. Specify a NumberFormatInfo or CultureInfo object for that parameter.

Integral and Floating-Point Numeric Types

Some descriptions of standard numeric format specifiers refer to integral or floating-point numeric types. The integral numeric types are Byte, SByte, Int16, Int32, Int64, UInt16, UInt32, and UInt64. The floating-point numeric types are Decimal, Single, and Double.

Floating-Point Infinities and NaN

Regardless of the format string, if the value of a Single or Double floating-point type is positive infinity, negative infinity, or not a number (NaN), the formatted string is the value of the respective PositiveInfinitySymbol, NegativeInfinitySymbol, or NaNSymbol property that is specified by the currently applicable NumberFormatInfo object.

Example

The following example formats an integral and a floating-point numeric value using the en-US culture and all the standard numeric format specifiers. This example uses two particular numeric types (Double and Int32), but would yield similar results for any of the other numeric base types (Byte, SByte, Int16, Int32, Int64, UInt16, UInt32, UInt64, Decimal, and Single).

Option Strict On

Imports System.Globalization
Imports System.Threading

Module Example
   Public Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
      ' Display string representations of numbers for en-us culture
      Dim ci As New CultureInfo("en-us")

      ' Output floating point values
      Dim floating As Double = 10761.937554
      outputBlock.Text += String.Format("C: {0}", _
              floating.ToString("C", ci))           ' Displays "C: $10,761.94" & vbCrLf
      outputBlock.Text += String.Format("E: {0}", _
              floating.ToString("E03", ci))         ' Displays "E: 1.076E+004" & vbCrLf
      outputBlock.Text += String.Format("F: {0}", _
              floating.ToString("F04", ci))         ' Displays "F: 10761.9376"          & vbCrLf
      outputBlock.Text += String.Format("G: {0}", _
              floating.ToString("G", ci))           ' Displays "G: 10761.937554" & vbCrLf
      outputBlock.Text += String.Format("N: {0}", _
              floating.ToString("N03", ci))         ' Displays "N: 10,761.938" & vbCrLf
      outputBlock.Text += String.Format("P: {0}", _
              (floating / 10000).ToString("P02", ci)) ' Displays "P: 107.62 %" & vbCrLf
      outputBlock.Text += String.Format("R: {0}", _
              floating.ToString("R", ci))           ' Displays "R: 10761.937554"             & vbCrLf
      outputBlock.Text += vbCrLf

      ' Output integral values
      Dim integral As Integer = 8395
      outputBlock.Text += String.Format("C: {0}", _
              integral.ToString("C", ci))           ' Displays "C: $8,395.00" & vbCrLf
      outputBlock.Text += String.Format("D: {0}", _
              integral.ToString("D6"))              ' Displays D: 008395""  & vbCrLf
      outputBlock.Text += String.Format("E: {0}", _
              integral.ToString("E03", ci))         ' Displays "E: 8.395E+003" & vbCrLf
      outputBlock.Text += String.Format("F: {0}", _
              integral.ToString("F01", ci))         ' Displays "F: 8395.0"     & vbCrLf
      outputBlock.Text += String.Format("G: {0}", _
              integral.ToString("G", ci))           ' Displays "G: 8395" & vbCrLf
      outputBlock.Text += String.Format("N: {0}", _
              integral.ToString("N01", ci))         ' Displays "N: 8,395.0" & vbCrLf
      outputBlock.Text += String.Format("P: {0}", _
              (integral / 10000).ToString("P02", ci)) ' Displays "P: 83.95 %" & vbCrLf
      outputBlock.Text += String.Format("X: 0x{0}", _
              integral.ToString("X", ci))           ' Displays "X: 0x20CB" & vbCrLf
      outputBlock.Text += vbCrLf
   End Sub
End Module

using System;
using System.Globalization;
using System.Threading;

public class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      // Display string representations of numbers for en-us culture
      CultureInfo ci = new CultureInfo("en-us");

      // Output floating point values
      double floating = 10761.937554;
      outputBlock.Text += String.Format("C: {0}",
              floating.ToString("C", ci)) + "\n";           // Displays "C: $10,761.94"
      outputBlock.Text += String.Format("E: {0}",
              floating.ToString("E03", ci)) + "\n";         // Displays "E: 1.076E+004"
      outputBlock.Text += String.Format("F: {0}",
              floating.ToString("F04", ci)) + "\n";         // Displays "F: 10761.9376"         
      outputBlock.Text += String.Format("G: {0}",
              floating.ToString("G", ci)) + "\n";           // Displays "G: 10761.937554"
      outputBlock.Text += String.Format("N: {0}",
              floating.ToString("N03", ci)) + "\n";         // Displays "N: 10,761.938"
      outputBlock.Text += String.Format("P: {0}",
              (floating / 10000).ToString("P02", ci)) + "\n"; // Displays "P: 107.62 %"
      outputBlock.Text += String.Format("R: {0}",
              floating.ToString("R", ci)) + "\n";           // Displays "R: 10761.937554"            
      outputBlock.Text += "\n";

      // Output integral values
      int integral = 8395;
      outputBlock.Text += String.Format("C: {0}",
              integral.ToString("C", ci)) + "\n";           // Displays "C: $8,395.00"
      outputBlock.Text += String.Format("D: {0}",
              integral.ToString("D6", ci)) + "\n";          // Displays D: 008395"" 
      outputBlock.Text += String.Format("E: {0}",
              integral.ToString("E03", ci)) + "\n";         // Displays "E: 8.395E+003"
      outputBlock.Text += String.Format("F: {0}",
              integral.ToString("F01", ci)) + "\n";         // Displays "F: 8395.0"    
      outputBlock.Text += String.Format("G: {0}",
              integral.ToString("G", ci)) + "\n";           // Displays "G: 8395"
      outputBlock.Text += String.Format("N: {0}",
              integral.ToString("N01", ci)) + "\n";         // Displays "N: 8,395.0"
      outputBlock.Text += String.Format("P: {0}",
              (integral / 10000).ToString("P02", ci)) + "\n"; // Displays "P: 83.95 %"
      outputBlock.Text += String.Format("X: 0x{0}",
              integral.ToString("X", ci)) + "\n";           // Displays "X: 0x20CB"
      outputBlock.Text += "\n";
   }
}

Change History

Date

History

Reason

October 2010

Noted that rounding away from zero is used with the "C" standard format string.

Customer feedback.