C# String Format()

using System;  
namespace CsharpString {  
  class Test {
    public static void Main(string [] args) {

      string name = "Programiz";
      // format string
      string strFormat = String.Format("Hello {0}", name);
      Console.WriteLine(strFormat);
    }
  } 
}
// Output: Hello Programiz

Format() Syntax

The syntax of the string Format() method is:

String.Format(String format, Object...args);

Here, Format() is a static method. Hence, we have used the class name String to call it.

Format() Parameters

The String.Format() method takes two parameters:

• format - a format string
• args - the object to format

Format() Return Value

The Format() method returns a formatted string.

Example 1: C# String Format()

// C# Program to insert the value of a single variable in a string

using System;  
namespace CsharpString {  
  class Test {
    public static void Main(string [] args) {

      int number = 2;
      // format string
      string strFormat = String.Format("There are {0} apples.", number);
      Console.WriteLine(strFormat);
    }
  } 
}

Output

There are 2 apples.

In the above code, notice the line

string strFormat = String.Format("There are {0} apples.", number);

Here,

• "There are {0} apples." is a format string
• {0} is the format item
• the variable number is inserted in the place of {0}

Example 2: C# Format() With Multiple Format Items

using System;  
namespace CsharpString {  
  class Test {
    public static void Main(string [] args) {

      string name = "Ed Sheeran";
      string food = "apple";

      // format string
      string strFormat = String.Format("{0} eats {1}", name, food);
      Console.WriteLine(strFormat);

      Console.ReadLine();
    }
  } 
}

Output

Ed Sheeran eats apple

In the above example, notice the line,

string strFormat = String.Format("{0} eats {1}", name, food);

Here,

• we have two format items {0} and {1}
• {0} is replaced by the first object passed in the method i.e. name
• {1} is replaced by the second object passed in the method i.e. food

Example 3: C# Format() - Control Spacing and Right Alignment

using System;  
namespace CsharpString {  
  class Test {
    public static void Main(string [] args) {

      // format string
      string strFormat = String.Format("{0, 20}", "Programiz");
      Console.WriteLine(strFormat);

      Console.ReadLine();
    }
  } 
}

Output

       	Programiz

In the above example, notice the line.

string strFormat = String.Format("{0, 20}", "Programiz");

Here,

• 0 represents the first object in the method
• 20 specifies the width of the string
• since 20 is a positive number, "Programiz" is right-aligned

Example 4: C# Format() - Control Spacing and Left Alignment

using System;  
namespace CsharpString {  
  class Test {
    public static void Main(string [] args) {

      // format string
      string strFormat = String.Format("{0, -20} {1, -14}", "Programiz", "C# Programming");
      Console.WriteLine(strFormat);

      Console.ReadLine();
    }
  } 
}

Output

Programiz        	C# Programming

In the above example, we have used the format string "{0, -20} {1, -14}". Here,

• 0 and 1 represent the first and second objects in the method ("Programiz" and "C# Programming")
• -20 and -14 represent the width of "Programiz" and "C# Programming" respectively.

Since -20 and -14 are negative numbers, "Programiz" and "C# Programming" are left-aligned.

using System;  
namespace CsharpString {  
  class Test {
    public static void Main(string [] args) {

      DateTime date = new DateTime(2015, 12, 31); 

       // format string 
      string strDate = String.Format("{0:D}", date);
      Console.WriteLine(strDate);

      Console.ReadLine();
    }
  } 
}

Thursday, December 31, 2015

string strDate = String.Format("{0:D}", date);

using System;  
namespace CsharpString {  
  class Test {
    public static void Main(string [] args) {

      // format string
      string strDecimal = String.Format("Decimal: {0:D}", 200);
      string strHexaDecimal = String.Format("Hexadecimal: {0:X}", 200);

      Console.WriteLine(strDecimal);
      Console.WriteLine(strHexaDecimal);

      Console.ReadLine();
    }
  } 
}

Decimal: 200
Hexadecimal: C8

string strDecimal = String.Format("Decimal: {0:D}", 200);

string strHexaDecimal = String.Format("Hexadecimal: {0:X}", 200);