Appendix C. Format Specifiers

Table C-1 lists the numeric format specifiers supported by the ToString method on the predefined numeric types (see Chapter 3).

Table C-1. Numeric format specifiers

Specifier

String result

Data type

C[n]

$XX,XX.XX

($XX,XXX.XX)

Currency

D[n]

[-]XXXXXXX

Decimal

E[n] or e[n]

[-]X.XXXXXXE+xxx

[-]X.XXXXXXe+xxx

[-]X.XXXXXXE-xxx

[-]X.XXXXXXe-xxx

Exponent

F[n]

[-]XXXXXXX.XX

Fixed point

G[n]

General or scientific

General

N[n]

[-]XX,XXX.XX

Number

P[n]

[-]XX,XXX.XX %

Percent

R

Round-trip format

Floating point

X[n] or x[n]

Hex representation

Hex

This is an example that uses numeric format specifiers without precision specifiers:

using System;
class TestDefaultFormats {
  static void Main(  ) {
    int i = 654321;
    Console.WriteLine("{0:C}", i); // $654,321.00
    Console.WriteLine("{0:D}", i); // 654321
    Console.WriteLine("{0:E}", i); // 6.543210E+005
    Console.WriteLine("{0:F}", i); // 654321.00
    Console.WriteLine("{0:G}", i); // 654321
    Console.WriteLine("{0:N}", i); // 654,321.00
    Console.WriteLine("{0:P}", i); // 65,432,100.00 %
    Console.WriteLine("{0:P}", .42); // 42.00 %
    Console.WriteLine("{0:X}", i); // 9FBF1
    Console.WriteLine("{0:x}", i); // 9fbf1
    // Round-trip conversions
    string s1 = Math.PI.ToString("G");
    Console.WriteLine(s1); // 3.14159265358979
    string s2 = Math.PI.ToString("R");
    Console.WriteLine(s2); // 3.1415926535897931
    Console.WriteLine(Math.PI == Double.Parse(s1)); // False
    Console.WriteLine(Math.PI == Double.Parse(s2)); // True
  }
}

This is an example that uses numeric format specifiers with precision specifiers on a variety of int values:

using System;
class TestIntegerFormats {
  static void Main(  ) {
    int i = 123;
    Console.WriteLine("{0:C6}", i); // $123.000000
    Console.WriteLine("{0:D6}", i); // 000123
    Console.WriteLine("{0:E6}", i); // 1.230000E+002
    Console.WriteLine("{0:G6}", i); // 123
    Console.WriteLine("{0:N6}", i); // 123.000000
    Console.WriteLine("{0:P6}", i); // 12,300.000000 %
    Console.WriteLine("{0:X6}", i); // 00007B
    i = -123;
    Console.WriteLine("{0:C6}", i); // ($123.000000)
    Console.WriteLine("{0:D6}", i); // -000123
    Console.WriteLine("{0:E6}", i); // -1.230000E+002
    Console.WriteLine("{0:G6}", i); // -123
    Console.WriteLine("{0:N6}", i); // -123.000000
    Console.WriteLine("{0:P6}", i); // -12,300.000000 %
    Console.WriteLine("{0:X6}", i); // FFFF85
    i = 0;
    Console.WriteLine("{0:C6}", i); // $0.000000
    Console.WriteLine("{0:D6}", i); // 000000
    Console.WriteLine("{0:E6}", i); // 0.000000E+000
    Console.WriteLine("{0:G6}", i); // 0
    Console.WriteLine("{0:N6}", i); // 0.000000
    Console.WriteLine("{0:P6}", i); // 0.000000 %
    Console.WriteLine("{0:X6}", i); // 000000
  }
}

Here’s an example that uses numeric format specifiers with precision specifiers on a variety of double values:

using System;
class TestDoubleFormats {
  static void Main(  ) {
    double d = 1.23;
    Console.WriteLine("{0:C6}", d); // $1.230000
    Console.WriteLine("{0:E6}", d); // 1.230000E+000
    Console.WriteLine("{0:G6}", d); // 1.23
    Console.WriteLine("{0:N6}", d); // 1.230000
    Console.WriteLine("{0:P6}", d); // 123.000000 %
    d = -1.23;
    Console.WriteLine("{0:C6}", d); // ($1.230000)
    Console.WriteLine("{0:E6}", d); // -1.230000E+000
    Console.WriteLine("{0:G6}", d); // -1.23
    Console.WriteLine("{0:N6}", d); // -1.230000
    Console.WriteLine("{0:P6}", d); // -123.000000 %
    d = 0;
    Console.WriteLine("{0:C6}", d); // $0.000000
    Console.WriteLine("{0:E6}", d); // 0.000000E+000
    Console.WriteLine("{0:G6}", d); // 0
    Console.WriteLine("{0:N6}", d); // 0.000000
    Console.WriteLine("{0:P6}", d); // 0.000000 %
  }
}

Picture Format Specifiers

Table C-2 lists the valid picture format specifiers supported by the ToStringmethod on t he predefined numeric types (see the documentation for System.IFormattable in the .NET SDK). The picture format can include up to three sections separated by a semicolon. With one section, the format specifier is applied to all values. With two sections, the first format specifier applies to zero and positive values, and the second applies to negative values. With three sections, the first specifier applies to positive values, the second applies to negative values, and the third applies to zero.

Table C-2. Picture format specifiers

Specifier

String result

0

Zero placeholder

#

Digit placeholder

.

Decimal point

,

Group separator or multiplier

%

Percent notation

E0, E+0, E-0, e0 e+0, e-0

Exponent notation

Literal character quote
'xx'"xx"
Literal string quote
;
Section separator
Here’s an example using picture format specifiers on some int values:
using System;
class TestIntegerCustomFormats {
  static void Main(  ) {
    int i = 123;
    Console.WriteLine("{0:#0}", i);             // 123
    Console.WriteLine("{0:#0;(#0)}", i);        // Two sections: 123
    Console.WriteLine("{0:#0;(#0);<zero>}", i); // Three sections: 123
    Console.WriteLine("{0:#%}", i);             // 12300%
    i = -123;
    Console.WriteLine("{0:#0}", i);             // -123
    Console.WriteLine("{0:#0;(#0)}", i);        // Two sections: (123)
    Console.WriteLine("{0:#0;(#0);<zero>}", i); // Three sections: (123)
    Console.WriteLine("{0:#%}", i);             // -12300%
    i = 0;
    Console.WriteLine("{0:#0}", i);             // 0
    Console.WriteLine("{0:#0;(#0)}", i);        // Two sections: 0
    Console.WriteLine("{0:#0;(#0);<zero>}", i); // Three sections: <zero>
    Console.WriteLine("{0:#%}", i);             // %
  }
}
The following is an example that uses these picture format
      specifiers on a variety of double
      values:
using System;
class TestDoubleCustomFormats {
  static void Main(  ) {
    double d = 1.23;
    Console.WriteLine("{0:#.000E+00}", d);    // 1.230E+00
    Console.WriteLine(
      "{0:#.000E+00;(#.000E+00)}", d);        // 1.230E+00
    Console.WriteLine(
      "{0:#.000E+00;(#.000E+00);<zero>}", d); // 1.230E+00
    Console.WriteLine("{0:#%}", d);           // 123%
    d = -1.23;
    Console.WriteLine("{0:#.000E+00}", d);    // -1.230E+00
    Console.WriteLine(
      "{0:#.000E+00;(#.000E+00)}", d);        // (1.230E+00)
    Console.WriteLine(
      "{0:#.000E+00;(#.000E+00);<zero>}", d); // (1.230E+00)
    Console.WriteLine("{0:#%}", d);           // -123%
    d = 0;
    Console.WriteLine("{0:#.000E+00}", d);    // 0.000E+01
    Console.WriteLine(
      "{0:#.000E+00;(#.000E+00)}", d);        // 0.000E+01
    Console.WriteLine(
      "{0:#.000E+00;(#.000E+00);<zero>}", d); // <zero>
    Console.WriteLine("{0:#%}", d);           // %
  }
}
DateTime Format Specifiers
Table C-3 lists
       the valid format specifiers supported by the Format method on the DateTime type (see System.IFormattable).
Table C-3. DateTime format specifiers
Specifier 
String result
d
MM/dd/yyyy
D
dddd, MMMM dd,               yyyy
f
dddd, MMMM dd, yyyy               HH:mm
F
dddd, MMMM dd, yyyy               HH:mm:ss
g
MM/dd/yyyy               HH:mm
G
MM/dd/yyyy               HH:mm:ss
m, M
MMMM               dd
r, R
Ddd, dd MMM yyyy HH:mm:ss               GMT
s
yyyy-MM-ddTHH:mm:ss
t
HH:mm
T
HH:mm:ss
u
yyyy-MM-dd               HH:mm:ssZ
U
dddd, MMMM dd, yyyy               HH:mm:ss
y, Y
MMMM,               yyyy
Here’s an example that uses these custom format specifiers on a
      DateTime value:
using System;
class TestDateTimeFormats {
  static void Main(  ) {
    DateTime dt = new DateTime(2000, 10, 11, 15, 32, 14);

    // Prints "10/11/2000 3:32:14 PM"
    Console.WriteLine(dt.ToString(  )); 
    // Prints "10/11/2000 3:32:14 PM"
    Console.WriteLine("{0}", dt);     
    // Prints "10/11/2000"
    Console.WriteLine("{0:d}", dt); 

    // Prints "Wednesday, October 11, 2000"
    Console.WriteLine("{0:D}", dt); 
    // Prints "Wednesday, October 11, 2000 3:32 PM"
    Console.WriteLine("{0:f}", dt); 
    // Prints "Wednesday, October 11, 2000 3:32:14 PM"
    Console.WriteLine("{0:F}", dt);  

    // Prints "10/11/2000 3:32 PM"
    Console.WriteLine("{0:g}", dt); 
    // Prints "10/11/2000 3:32:14 PM"
    Console.WriteLine("{0:G}", dt);

    // Prints "October 11"
    Console.WriteLine("{0:m}", dt);
    // Prints "October 11"
    Console.WriteLine("{0:M}", dt);

    // Prints "Wed, 11 Oct 2000 15:32:14 GMT"
    Console.WriteLine("{0:r}", dt); 
    // Prints "Wed, 11 Oct 2000 15:32:14 GMT"
    Console.WriteLine("{0:R}", dt); 

    // Prints "3:32 PM"
    Console.WriteLine("{0:t}", dt); 
    // Prints "3:32:14 PM"
    Console.WriteLine("{0:T}", dt); 

    // Prints "2000-10-11T15:32:14"
    Console.WriteLine("{0:s}", dt); 
    // Prints "2000-10-11 15:32:14Z"
    Console.WriteLine("{0:u}", dt); 
    // Prints "Wednesday, October 11, 2000 7:32:14 PM"
    Console.WriteLine("{0:U}", dt); 

    // Prints "October, 2000"
    Console.WriteLine("{0:y}", dt); 
    // Prints "October, 2000"
    Console.WriteLine("{0:Y}", dt); 
    // Prints "Wednesday the 11 day of October in the year 2000"
    Console.WriteLine(
      "{0:dddd 'the' d 'day of' MMMM 'in the year' yyyy}", dt);
  }
}

		

		  






						
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