C#

string str = "ABC-X-Y-Z";
int index = str.IndexOf("-");
str = String.Format("{0}{1}{2}", str.Substring(0, index), ".", str.Substring(index + 1, str.Length - index - 1));

  string str= "xyz-x-y-z";<br />
        int i = str.IndexOf("-");<br />
        str = str.Insert(i+1, ".").Remove(i, 1);<br />
<br />

Pankaj - Joshi wrote:

public static string getNewItemName(string actualItemName, string saparaterCharacter)
{
string valueToReturn = "";
try
{
int ipos = actualItemName.ToString().IndexOf(saparaterCharacter.ToString());
if (ipos > -1) //That means saparator is not found...
{
if (saparaterCharacter.ToString().Length == 0)
valueToReturn = actualItemName.ToString();
else
{
string strFirstPart = actualItemName.ToString().Substring(0, ipos).ToString();
string strSecondPart = "";
if (actualItemName.ToString().Length == 0)
strSecondPart = actualItemName.ToString().Substring(ipos).ToString();
else
strSecondPart = actualItemName.ToString().Substring(ipos + 1).ToString();

valueToReturn = strFirstPart + ":" + strSecondPart;
}
}
else
valueToReturn = actualItemName.ToString();
}
catch (Exception)
{
//In Case of any error we are returning the same name
valueToReturn = actualItemName.ToString();
}
return valueToReturn;
}

string str = "ABC-X-Y-Z";
int index = str.IndexOf("-");
if (index>=0) str = str.Substring(0,index)+ "." + str.Substring(index+1);

if ( args.Length > 2 )
{
    int index = args [ 0 ].IndexOf ( args [ 1 ] ) ;
 
    if ( index >= 0 )
    {
        args [ 0 ] = (new System.Text.StringBuilder ( args [ 0 ] )).Replace ( args [ 1 ] , args [ 2 ] , index , args [ 1 ].Length ).ToString() ;
    }
 
    System.Console.WriteLine ( args [ 0 ] ) ;
}

public static string
Replace
(
    string Subject
,
    string Old
,
    string New
,
    ushort MaxReplacements
)
{
    System.Text.StringBuilder result = new System.Text.StringBuilder ( Subject.Length ) ;
    string[] parts = Subject.Split
    (
        new string[] { Old }
    ,
        (int) MaxReplacements+1
    ,
        System.StringSplitOptions.None
    ) ;

    result.Append ( parts [ 0 ] ) ;

    for ( int runner = 1 ; runner < parts.Length ; runner++ )
    {
        result.Append ( New ) ;
        result.Append ( parts [ runner ] ) ;
    }

    return ( result.ToString() ) ;
}

public static string
Replace
(
    string Subject     
,
    string Old  
,
    string New      
,
    ushort MaxReplacements
)
{
    return ( string.Join 
    ( 
        New 
    ,
        Subject.Split 
        ( 
            new string[] { Old } 
        , 
            (int) MaxReplacements+1 
        , 
            System.StringSplitOptions.None 
        ) 
    ) ) ;
}