Application of the string join method

Case 1:

View code

Using System;

Class Program
{
Static Void Main ()
{
String [] Arr = { " One " ," Two " , " Three " };
Console. writeline ( String . Join ( " , " , Arr )); // "String" can be lowercase, or
Console. writeline (string. Join (" , " , Arr )); // "String" can be uppercase
}
}

Output result:

 

 
One, two, three
One, two, three

Case 2:
 

View code Using System;

Class Program
{
Static Void Main ()
{
// Problem: combine these words into lines in HTML
String [] Din1_urs = New String [] { " Aeolosaurus " ,
" Deinonychus " , " Jaxartosaurus " , " Segnosaurus " };

//Solution: Join with break tag.
StringHtml =String. Join ("<Br/> \ r \ n", Dinosaurs );
Console. writeline (HTML );
}
}

 
Output result:
Aeolosaurus <br/>
Deinonychus <br/>
Jaxartosaurus <br/>
Segnosaurus

Case 3:
 

View code Using System;
Using System. text;

Class Program
{
Static Void Main ()
{
String [] Catspecies = { " Aegean " , " Birman " , " Main coon " , " Nebulung " };
Console. writeline (combinea (catspecies ));
Console. writeline (combineb (catspecies ));
}

///   <Summary>
/// Combine strings with commas.
///   </Summary>
Static String Combinea ( String [] ARR)
{
Return String . Join ( " , " , Arr );
}

///   <Summary>
/// Combine strings with commas.
///   </Summary>
Static String Combineb ( String [] ARR)
{
Stringbuilder builder = New Stringbuilder ();
Foreach ( String S In ARR)
{
Builder. append (s). append ( " , " );
}
Return Builder. tostring (). trimend ( New Char [] { ' , ' });
}
}

Output result:
 
Aegean, Birman, main coon, nebulung
Aegean, Birman, main coon, nebulung

Case 4:

 
View code  Using System;
 
 
 Class Program
{
 Static  Void Main ()
{
 Try 
{
 String Bug = String . Join (Null , Null ); //  Null arguments are bad  
 }
 Catch (Exception ex)
{
Console. writeline (Ex );
}
}
}
 
Output result:
 
System. argumentnullexception: value cannot be null.
Parameter Name: Value

Case 5:

 
 View code  Using System;
 Using System. Collections. Generic;
 
 
 Class Program
{
 Static  Void Main ()
{
 // List of cities  
 List < String > Cities = New List < String > ();
Cities. Add ( "  New York  " );
Cities. Add ( "  Mumbai  " );
Cities. Add ( "  Berlin  " );
Cities. Add ( "  Istanbul  " );
//Join strings into one CSV line
StringLine =String. Join (",", Cities. toarray ());
Console. writeline (line );
}
}
 
 
New York, Mumbai, Berlin, Istanbul
Conclusion: compared with the stringbuilder method, the join method has a much higher performance. Some people have tested 1000000 pieces of data. The two methods are time-consuming:
String. Join:157 MS 
Stringbuilder append method:270 MS