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==Basic String functionality==

<source lang="csharp">using System;
using System.Collections.Generic;
using System.Text;

class Program
{
static void Main(string[] args)
{
string firstName = "Buddy";
Console.WriteLine("Value of firstName: {0}", firstName);
Console.WriteLine("firstName has {0} characters.", firstName.Length);
Console.WriteLine("firstName in uppercase: {0}", firstName.ToUpper());
Console.WriteLine("firstName in lowercase: {0}", firstName.ToLower());
Console.WriteLine("firstName contains the letter y?: {0}", firstName.Contains("y"));
Console.WriteLine("firstName after replace: {0}", firstName.Replace("dy", ""));
}
}</source>

==Declaration of string==

<OL><LI>strings are objects.</LI><LI>string is a reference type.</LI></OL>
<OL><LI>static string Copy(string str)</LI><LI>int CompareTo(string str)</LI><LI>int IndexOf(string str)</LI><LI>int LastIndexOf(string str)</LI><LI>string ToLower( )</LI><LI>string ToUpper( )</LI></OL>
<p>A string is a set of characters enclosed by double quotes. For example,</p>

<source lang="csharp">"this is a test"</source>

==Display all the characters in myString using a for loop==

<source lang="csharp">using System;
class MainClass
{
public static void Main()
{
string myString = "To be or not to be";

for (int count = 0; count < myString.Length; count++)
{
Console.WriteLine("myString[" + count + "] = " + myString[count]);
}
}
}</source>
<pre class=codeResult>myString[0] = T
myString[1] = o
myString[2] =
myString[3] = b
myString[4] = e
myString[5] =
myString[6] = o
myString[7] = r
myString[8] =
myString[9] = n
myString[10] = o
myString[11] = t
myString[12] =
myString[13] = t
myString[14] = o
myString[15] =
myString[16] = b
myString[17] = e</pre>

==Empty string==

<source lang="csharp">using System;
using System.IO;
using System.Text;
public class MainClass
{
public static void Main(string[] args)
{
string address = String.Empty;
}
}</source>

==Error; string Is Immutable==

<source lang="csharp">class Uppercase
{
static void Main()
{
string text;
System.Console.Write("Enter text: ");
text = System.Console.ReadLine();
text.ToUpper();
System.Console.WriteLine(text);
}
}</source>

==String are immutable==

<source lang="csharp">using System;
using System.Collections.Generic;
using System.Text;

class Program
{
static void Main(string[] args)
{
// Set initial string value.
string s1 = "This is my string.";
Console.WriteLine("s1 = {0}", s1);
// Uppercase the s1?
string upperString = s1.ToUpper();
Console.WriteLine("upperString = {0}", upperString);
// Nope! s1 is in the same format!
Console.WriteLine("s1 = {0}", s1);
string s2 = "My other string";
s2 = "New string value";
}
}</source>

==String is object==

<source lang="csharp">using System;
class MainClass
{
static void Main(string[] args) {
string strOriginal = "Original String";
Console.WriteLine( "Value of strOriginal before call: {0}", strOriginal );
TryToAlterString( strOriginal );
Console.WriteLine( "Value of strOriginal after call: {0}", strOriginal );
}
static void TryToAlterString(string str) {
str = "Modified String";
}
}</source>
<pre class=codeResult>Value of strOriginal before call: Original String
Value of strOriginal after call: Original String</pre>

==Use Indexer to reference chars in a string==

<source lang="csharp">using System;
class MainClass
{
public static void Main()
{
string myString = "To be or not to be";

for (int count = 0; count < myString.Length; count++)
{
Console.WriteLine("myString[" + count + "] = " + myString[count]);
}
}
}</source>
<pre class=codeResult>myString[0] = T
myString[1] = o
myString[2] =
myString[3] = b
myString[4] = e
myString[5] =
myString[6] = o
myString[7] = r
myString[8] =
myString[9] = n
myString[10] = o
myString[11] = t
myString[12] =
myString[13] = t
myString[14] = o
myString[15] =
myString[16] = b
myString[17] = e</pre>

==Use the addition operator (+) to concatenate strings==

<source lang="csharp">using System;
class MainClass
{
public static void Main()
{
string myString6 = "To be, " + "or not to be";
Console.WriteLine("\"To be, \" + \"or not to be\" = " + myString6);
}
}</source>
<pre class=codeResult>"To be, " + "or not to be" = To be, or not to be</pre>

==Use the Compare() method to compare strings==

<source lang="csharp">using System;
class MainClass
{
public static void Main()
{

int result;
result = String.rupare("bbc", "abc");
Console.WriteLine("String.rupare(\"bbc\", \"abc\") = " + result);
result = String.rupare("abc", "bbc");
Console.WriteLine("String.rupare(\"abc\", \"bbc\") = " + result);
result = String.rupare("bbc", "bbc");
Console.WriteLine("String.rupare(\"bbc\", \"bbc\") = " + result);
result = String.rupare("bbc", "BBC", true);
Console.WriteLine("String.rupare(\"bbc\", \"BBC\", true) = " + result);
result = String.rupare("bbc", "BBC", false);
Console.WriteLine("String.rupare(\"bbc\", \"BBC\", false) = " + result);
result = String.rupare("Hello World", 6, "Goodbye World", 8, 5);
Console.WriteLine("String.rupare(\"Hello World\", 6, " + "\"Goodbye World\", 8, 5) = " + result);
}
}</source>
<pre class=codeResult>String.rupare("bbc", "abc") = 1
String.rupare("abc", "bbc") = -1
String.rupare("bbc", "bbc") = 0
String.rupare("bbc", "BBC", true) = 0
String.rupare("bbc", "BBC", false) = -1
String.rupare("Hello World", 6, "Goodbye World", 8, 5) = 0</pre>

==Use the Concat() method to concatenate strings==

<source lang="csharp">using System;
class MainClass
{
public static void Main()
{
string myString4 = String.Concat("A, ", "B");
Console.WriteLine("String.Concat(\"A, \", \"B\") = "+ myString4);
string myString5 = String.Concat("A, ", "B, ", "and countrymen");
Console.WriteLine("String.Concat(\"A, \", \"B, \", " + "\"and countrymen\") = " + myString5);
}
}</source>
<pre class=codeResult>String.Concat("A, ", "B") = A, B
String.Concat("A, ", "B, ", "and countrymen") = A, B, and countrymen</pre>

==Use the Copy() method to copy a string==

<source lang="csharp">using System;
class MainClass
{
public static void Main()
{

string myString4 = "string4";
Console.WriteLine("myString4 = " + myString4);
Console.WriteLine("Copying myString4 to myString7 using Copy()");
string myString7 = String.Copy(myString4);
Console.WriteLine("myString7 = " + myString7);
}
}</source>
<pre class=codeResult>myString4 = string4
Copying myString4 to myString7 using Copy()
myString7 = string4</pre>

==Use the Equals() method and equality operator to check if two strings are equal==

<source lang="csharp">using System;
class MainClass
{
public static void Main()
{
bool boolResult;
string myString = "str";
string myString2 = "str2";

boolResult = String.Equals("bbc", "bbc");
Console.WriteLine("String.Equals(\"bbc\", \"bbc\") is " + boolResult);

boolResult = myString.Equals(myString2);
Console.WriteLine("myString.Equals(myString2) is " + boolResult);

boolResult = myString == myString2;
Console.WriteLine("myString == myString2 is " + boolResult);
}
}</source>
<pre class=codeResult>String.Equals("bbc", "bbc") is True
myString.Equals(myString2) is False
myString == myString2 is False</pre>

==Use the Format() method to format a string==

<source lang="csharp">using System;
class MainClass
{
public static void Main()
{

float myFloat = 1234.56789f;
string myString8 = String.Format("{0, 10:f3}", myFloat);
Console.WriteLine("String.Format(\"{0, 10:f3}\", myFloat) = " + myString8);
}
}</source>
<pre class=codeResult>String.Format("{0, 10:f3}", myFloat) = 1234.568</pre>

==Use the IndexOfAny() and LastIndexOfAny() methods to search for character arrays in a string==

<source lang="csharp">using System;
class MainClass
{
public static void Main()
{
string[] myStrings = {"To", "be", "or", "not", "to", "be"};
string myString = String.Join(".", myStrings);

char[] myChars = {"b", "e"};
int index = myString.IndexOfAny(myChars);
Console.WriteLine(""b" and "e" occur at index " + index + " of myString");
index = myString.LastIndexOfAny(myChars);
Console.WriteLine(""b" and "e" last occur at index " + index + " of myString");
}
}</source>
<pre class=codeResult>"b" and "e" occur at index 3 of myString
"b" and "e" last occur at index 17 of myString</pre>

==Use the Insert(), Remove(), and Replace() methods to modify strings==

<source lang="csharp">using System;
class MainClass
{
public static void Main()
{
string[] myStrings = {"To", "be", "or", "not", "to", "be"};
string myString = String.Join(".", myStrings);

string myString10 = myString.Insert(6, "A, ");
Console.WriteLine("myString.Insert(6, \"A, \") = " + myString10);
string myString11 = myString10.Remove(14, 7);
Console.WriteLine("myString10.Remove(14, 7) = " + myString11);
string myString12 = myString11.Replace(",", "?");
Console.WriteLine("myString11.Replace(",", "?") = " + myString12);
string myString13 = myString12.Replace("to be", "Or not to be A");
Console.WriteLine("myString12.Replace(\"to be\", \"Or not to be A\") = " + myString13);
}
}</source>
<pre class=codeResult>myString.Insert(6, "A, ") = To.be.A, or.not.to.be
myString10.Remove(14, 7) = To.be.A, or.no
myString11.Replace(",", "?") = To.be.A? or.no
myString12.Replace("to be", "Or not to be A") = To.be.A? or.no</pre>

==Use the Join() method to join strings==

<source lang="csharp">using System;
class MainClass
{
public static void Main()
{

string[] myStrings = {"To", "be", "or", "not", "to", "be"};
string myString9 = String.Join(".", myStrings);
Console.WriteLine("myString9 = " + myString9);
}
}</source>
<pre class=codeResult>myString9 = To.be.or.not.to.be</pre>

==Use the PadLeft() and PadRight() methods to align strings==

<source lang="csharp">using System;
class MainClass
{
public static void Main()
{
string[] myStrings = {"To", "be", "or", "not", "to", "be"};
string myString = String.Join(".", myStrings);

string myString14 = "(" + myString.PadLeft(20) + ")";
Console.WriteLine(""(" + myString.PadLeft(20) + ")" = " + myString14);
string myString15 = "(" + myString.PadLeft(20, ".") + ")";
Console.WriteLine(""(" + myString.PadLeft(20, ".") = " + myString15);
string myString16 = "(" + myString.PadRight(20) + ")";
Console.WriteLine(""(" + myString.PadRight(20) + ")" = " + myString16);
string myString17 = "(" + myString.PadRight(20, ".") + ")";
Console.WriteLine(""(" + myString.PadRight(20, ".") + ")" = " + myString17);
}
}</source>
<pre class=codeResult>"(" + myString.PadLeft(20) + ")" = ( To.be.or.not.to.be)
"(" + myString.PadLeft(20, ".") = (..To.be.or.not.to.be)
"(" + myString.PadRight(20) + ")" = (To.be.or.not.to.be )
"(" + myString.PadRight(20, ".") + ")" = (To.be.or.not.to.be..)</pre>

==Use the Split() method to split strings==

<source lang="csharp">using System;
class MainClass
{
public static void Main()
{
string[] myStrings = {"To", "be", "or", "not", "to", "be"};
string myString9 = String.Join(".", myStrings);
myStrings = myString9.Split(".");
foreach (string mySplitString in myStrings)
{
Console.WriteLine("mySplitString = " + mySplitString);
}
}
}</source>
<pre class=codeResult>mySplitString = To
mySplitString = be
mySplitString = or
mySplitString = not
mySplitString = to
mySplitString = be</pre>

==Use the Substring() method to retrieve substrings==

<source lang="csharp">using System;
class MainClass
{
public static void Main()
{

string[] myStrings = {"To", "be", "or", "not", "to", "be"};
string myString = String.Join(".", myStrings);

string myString21 = myString.Substring(3);
Console.WriteLine("myString.Substring(3) = " + myString21);
string myString22 = myString.Substring(3, 2);
Console.WriteLine("myString.Substring(3, 2) = " + myString22);
}
}</source>
<pre class=codeResult>myString.Substring(3) = be.or.not.to.be
myString.Substring(3, 2) = be</pre>

==Use the Trim(), TrimStart(), and TrimEnd() methods to trim strings==

<source lang="csharp">using System;
class MainClass
{
public static void Main()
{

string myString18 = "(" + " Whitespace ".Trim() + ")";
Console.WriteLine(""(" + \" Whitespace \".Trim() + ")" = " + myString18);
string myString19 = "(" + " Whitespace ".TrimStart() + ")";
Console.WriteLine(""(" + \" Whitespace \".TrimStart() + ")" = " + myString19);
string myString20 = "(" + " Whitespace ".TrimEnd() + ")";
Console.WriteLine(""(" + \" Whitespace \".TrimEnd() + ")" = " + myString20);
}
}</source>
<pre class=codeResult>"(" + " Whitespace ".Trim() + ")" = (Whitespace)
"(" + " Whitespace ".TrimStart() + ")" = (Whitespace )
"(" + " Whitespace ".TrimEnd() + ")" = ( Whitespace)</pre>

==Working with Strings==

<source lang="csharp">class Uppercase
{
static void Main()
{
System.Console.Write("Enter text: ");
var text = System.Console.ReadLine();
var uppercase = text.ToUpper();
System.Console.WriteLine(uppercase);
}
}</source>

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