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Double.Parse Method (String)

Converts the string representation of a number to its double-precision floating-point number equivalent.

Namespace: System
Assembly: mscorlib (in mscorlib.dll)

public static double Parse (
	string s
)
public static double Parse (
	String s
)
public static function Parse (
	s : String
) : double
Not applicable.

Parameters

s

A string containing a number to convert.

Return Value

A double-precision floating-point number equivalent to the numeric value or symbol specified in s.

Exception typeCondition

ArgumentNullException

s is a null reference (Nothing in Visual Basic).

FormatException

s is not a number in a valid format.

OverflowException

s represents a number less than MinValue or greater than MaxValue.

The s parameter can contain PositiveInfinitySymbol, NegativeInfinitySymbol, NaNSymbol, or a string of the form:

[ws][sign][integral-digits[,]]integral-digits[.[fractional-digits]][e[sign]exponential-digits][ws]

Elements in square brackets ([ and ]) are optional. The following table describes each element.

Element

Description

ws

A series of white space characters.

sign

A negative sign or positive sign symbol. Only a leading sign can be used.

integral-digits

A series of digits ranging from 0 to 9 that specify the integral part of the number. Runs of integral-digits can be partitioned by a group-separator symbol. (For example, in some cultures a comma (,) separates groups of thousands.) Integral-digits can be absent if there are fractional-digits.

,

A culture-specific thousands separator symbol.

.

A culture-specific decimal point symbol.

fractional-digits

A series of digits ranging from 0 to 9 that specify the fractional part of the number.

E

An uppercase or lowercase character 'e', indicating exponential (scientific) notation.

exponential-digits

A series of digits ranging from 0 to 9 that specify an exponent.

The s parameter is interpreted using a combination of the NumberStyles.Float and NumberStyles.AllowThousands flags. This means that white space and thousands separators are allowed, for example, while currency symbols are not. For finer control over which style elements are permitted in s for the parse operation to succeed, call the Double.Parse(String,NumberStyles) or the Double.Parse(String,NumberStyles,IFormatProvider) method.

The s parameter is interpreted using the formatting information in a NumberFormatInfo object that is initialized for the current thread culture. For more information, see CurrentInfo. To parse a string using the formatting information of some other culture, call the Byte.Parse(String,IFormatProvider) or Byte.Parse(String,NumberStyles,IFormatProvider) method.

If a separator is encountered in the s parameter during a parse operation, and the applicable currency or number decimal and group separators are the same, the parse operation assumes that the separator is a decimal separator rather than a group separator. For more information about separators, see CurrencyDecimalSeparator, NumberDecimalSeparator, CurrencyGroupSeparator, and NumberGroupSeparator.

The following code example illustrates the use of Parse, taking a String as a parameter:

public class Temperature {
    /// <summary>
    /// Parses the temperature from a string in form
    /// [ws][sign]digits['F|'C][ws]
    /// </summary>
    public static Temperature Parse(string s) {
        Temperature temp = new Temperature();

        if( s.TrimEnd(null).EndsWith("'F") ) {
            temp.Value = Double.Parse( s.Remove(s.LastIndexOf('\''), 2) );
        }
        else if( s.TrimEnd(null).EndsWith("'C") ) {
            temp.Celsius = Double.Parse( s.Remove(s.LastIndexOf('\''), 2) );
        }
        else {
            temp.Value = Double.Parse(s);
        }

        return temp;
    }

    // The value holder
    protected double m_value;

    public double Value {
        get {
            return m_value;
        }
        set {
            m_value = value;
        }
    }

    public double Celsius {
        get {
            return (m_value-32.0)/1.8;
        }
        set {
            m_value = 1.8*value+32.0;
        }
    }
}

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

XNA Framework

Supported in: 1.0

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