Csharp/CSharp Tutorial/String/StringBuilder

Add formatted string to StringBuilder

<source lang="csharp">using System; using System.Text; class MainClass {

   public static void Main()
   {
       StringBuilder sb = new StringBuilder();
       int number = 1;
       sb.AppendFormat("{0}: {1} ", number++, "another string");
       Console.WriteLine("{0}", sb);
   }

}</source>

1: another string

Append("A ").Append("B ").Append("C... ")

<source lang="csharp">using System; using System.Text; public class MainClass {

   static void Main() {
       StringBuilder sb = new StringBuilder();
       sb.Append("A ").Append("B ").Append("C... ");
       string built1 = sb.ToString();
       sb.Append("D");
       string built2 = sb.ToString();
       Console.WriteLine( built1 );
       Console.WriteLine( built2 );
   }

}</source>

A B C...
A B C... D

Append string and insert string to a StringBuilder

<source lang="csharp">using System; using System.Text; class MainClass {

 static void Main(string[] args)
 {
     StringBuilder MyString = new StringBuilder("Hello");
   
     MyString.Insert(0, "My");
     MyString.Append("World");
   
     Console.WriteLine(MyString);
 }

}</source>

MyHelloWorld

Display the contents of StringBuilder

<source lang="csharp">using System; using System.Text; class MainClass {

 public static void Main()
 {
   StringBuilder myStringBuilder = new StringBuilder();
   
   myStringBuilder.Append("myString");
   
   
   myStringBuilder.Append("Here"s another string", 0, 4);

   Console.WriteLine(myStringBuilder);
 }

}</source>

myStringHere

Set Length property of StringBuilder

<source lang="csharp">using System; using System.Text; class MainClass {

   public static void Main()
   {
     StringBuilder sb = new StringBuilder("test string");
     int length = 0;
   
     length = sb.Length;
     Console.WriteLine("The result is: "{0}"", sb);
     Console.WriteLine("The length is: {0}", length);
   
     sb.Length = 4;
     length = sb.Length;
     Console.WriteLine("The result is: "{0}"", sb);
     Console.WriteLine("The length is: {0}", length);
   
     sb.Length = 20;
     length = sb.Length;
     Console.WriteLine("The result is: "{0}"", sb);
     Console.WriteLine("The length is: {0}", length);
   }

}</source>

The result is: "test string"
The length is: 11
The result is: "test"
The length is: 4
The result is: "test                "
The length is: 20

StringBuilder: append value with format

<source lang="csharp">using System; using System.Collections.Generic; using System.Globalization; using System.IO; using System.Text; using System.Security.Cryptography; public class MainClass {

   public static void Main()
   {
       StringBuilder sb = new StringBuilder("Foo");
       sb.AppendFormat("...{0}", DateTime.Now);
       string final = sb.ToString();
       Console.WriteLine(final);
   }

}</source>

Foo...25/03/2007 3:03:25 PM

StringBuilder: Length, Capacity, MaxCapacity

<source lang="csharp">using System; using System.Text; class MainClass {

 public static void DisplayProperties(string name,StringBuilder myStringBuilder)
 {
   Console.WriteLine(name + ".Length = " + myStringBuilder.Length);
   Console.WriteLine(name + ".Capacity = " + myStringBuilder.Capacity);
   Console.WriteLine(name + ".MaxCapacity = " + myStringBuilder.MaxCapacity);
 }
 public static void Main()
 {
   StringBuilder myStringBuilder = new StringBuilder();
   int capacity = 50;
   StringBuilder myStringBuilder2 = new StringBuilder(capacity);
   int maxCapacity = 100;
   StringBuilder myStringBuilder3 = new StringBuilder(capacity, maxCapacity);
   string myString = "To be or not to be";
   StringBuilder myStringBuilder4 = new StringBuilder(myString);
   int startIndex = 0;
   int stringLength = myString.Length;
   StringBuilder myStringBuilder5 = new StringBuilder(myString, startIndex, stringLength, capacity);
   DisplayProperties("myStringBuilder", myStringBuilder);
   DisplayProperties("myStringBuilder2", myStringBuilder2);
   DisplayProperties("myStringBuilder3", myStringBuilder3);
   DisplayProperties("myStringBuilder4", myStringBuilder4);
   DisplayProperties("myStringBuilder5", myStringBuilder5);
 }

}</source>

myStringBuilder.Length = 0
myStringBuilder.Capacity = 16
myStringBuilder.MaxCapacity = 2147483647
myStringBuilder2.Length = 0
myStringBuilder2.Capacity = 50
myStringBuilder2.MaxCapacity = 2147483647
myStringBuilder3.Length = 0
myStringBuilder3.Capacity = 50
myStringBuilder3.MaxCapacity = 100
myStringBuilder4.Length = 18
myStringBuilder4.Capacity = 32
myStringBuilder4.MaxCapacity = 2147483647
myStringBuilder5.Length = 18
myStringBuilder5.Capacity = 50
myStringBuilder5.MaxCapacity = 2147483647

Use StringBuilder to reverse a string

<source lang="csharp">using System; using System.Text; class MainClass {

   public static void Main()
   {
       string str = "www.nfex.ru";
       
       StringBuilder revStr = new StringBuilder();
       for (int count = str.Length - 1; count > -1; count--)
       {
           revStr.Append(str[count]);
       }
       
       Console.WriteLine(revStr.ToString());
   }

}</source>

moc.s2avaj.www

Use the AppendFormat() method to add a formatted string containing a floating point number to myStringBuilder

<source lang="csharp">using System; using System.Text; class MainClass {

 public static void Main()
 {
   StringBuilder myStringBuilder = new StringBuilder();
   myStringBuilder.Append("friends");
   
   float myFloat = 1234.56789f;
   myStringBuilder.AppendFormat("{0, 10:f3}", myFloat);
   Console.WriteLine("myStringBuilder = " + myStringBuilder);
   Console.WriteLine(myStringBuilder);
 }

}</source>

myStringBuilder = friends  1234.568
friends  1234.568

Use the Append() method to append a character to StringBuilder

<source lang="csharp">using System; using System.Text; class MainClass {

 public static void Main()
 {
   StringBuilder myStringBuilder = new StringBuilder();
   
   myStringBuilder.Append("myString");
   
   myStringBuilder.Append("z", 5);

   Console.WriteLine(myStringBuilder);
 }

}</source>

myStringzzzzz

Use the Append() method to append a substring to StringBuilder

<source lang="csharp">using System; using System.Text; class MainClass {

 public static void Main()
 {
   StringBuilder myStringBuilder = new StringBuilder();
   
   myStringBuilder.Append("myString");
   
   
   myStringBuilder.Append("Here"s another string", 0, 4);

   Console.WriteLine(myStringBuilder);
 }

}</source>

myStringHere

Use the Append() method to append two strings, an int, and a bool to StringBuilder

<source lang="csharp">using System; using System.Text; class MainClass {

 public static void Main()
 {
   StringBuilder myStringBuilder = new StringBuilder();
   
   myStringBuilder.Append("myString");
   myStringBuilder.Append(" ... ");
   int myInt = 1234;
   myStringBuilder.Append(myInt);
   bool myBool = true;
   myStringBuilder.Append(myBool);

   Console.WriteLine(myStringBuilder);
 }

}</source>

myString ... 1234True

Use the Insert() method to insert strings into StringBuilder

<source lang="csharp">using System; using System.Text; class MainClass {

 public static void Main()
 {
   StringBuilder myStringBuilder = new StringBuilder();
   myStringBuilder.Append("friends");
   
   myStringBuilder.Insert(2, "friends, ");
   myStringBuilder.Insert(2, "Romans, ", 3);
   Console.WriteLine("myStringBuilder = " + myStringBuilder);
 }

}</source>

Use the Remove() method to remove part of StringBuilder

<source lang="csharp">using System; using System.Text; class MainClass {

 public static void Main()
 {
   StringBuilder myStringBuilder = new StringBuilder();
   myStringBuilder.Append("friends");
   
   myStringBuilder.Insert(2, "friends, ");
   myStringBuilder.Insert(2, "Romans, ", 3);
   Console.WriteLine("myStringBuilder = " + myStringBuilder);
   
   myStringBuilder.Remove(4, 7);
   Console.WriteLine("myStringBuilder = " + myStringBuilder);
 }

}</source>

Use the Replace() method to replace part of StringBuilder

<source lang="csharp">using System; using System.Text; class MainClass {

 public static void Main()
 {
   StringBuilder myStringBuilder = new StringBuilder();
   myStringBuilder.Append("friends");
   
   myStringBuilder.Insert(2, "friends, ");
   myStringBuilder.Insert(2, "Romans, ", 3);
   Console.WriteLine("myStringBuilder = " + myStringBuilder);
   
   myStringBuilder.Replace(",", "?");
   Console.WriteLine("myStringBuilder = " + myStringBuilder);
 }

}</source>

Use the ToString() method to convert StringBuilder to a string

<source lang="csharp">using System; using System.Text; class MainClass {

 public static void Main()
 {
   StringBuilder myStringBuilder = new StringBuilder();
   
   
   myStringBuilder.Append("friends");
   
   string myString2 = myStringBuilder.ToString();
   Console.WriteLine("myString2 = " + myString2);
 }

}</source>

myString2 = friends