The String.Join Method in C# Explained

The String.Join Method in C#

 The string.Join concatenates the elements of a specified array or the members of a collection, using the specified separator between each element or member.

Overloads of string.Join

Method	Description
Join(Char, Object[])	Concatenates the string representations of an array of objects, using the specified separator between each member.
Join(Char, String[])	Concatenates an array of strings, using the specified separator between each member.
Join(String, IEnumerable<String>)	Concatenates the members of a constructed IEnumerable<T> collection of type String, using the specified separator between each member.
Join(String, Object[])	Concatenates the elements of an object array, using the specified separator between each element.
Join(String, String[])	Concatenates all the elements of a string array, using the specified separator between each element.
Join(Char, String[], Int32, Int32)	Concatenates an array of strings, using the specified separator between each member, starting with the element in value located at the startIndex position, and concatenating up to count elements.
Join(String, String[], Int32, Int32)	Concatenates the specified elements of a string array, using the specified separator between each element.
Join<T>(Char, IEnumerable<T>)	Concatenates the members of a collection, using the specified separator between each member.
Join<T>(String, IEnumerable<T>)	Concatenates the members of a collection, using the specified separator between each member.

 

Syntax and Examples of some join Overloads

Join(Char, Object[])

Concatenates the string representations of an array of objects, using the specified separator between each member.

public static string Join(char separator, params object[] values);

 

Parameters

Separator Char

The character to use as a separator. Separator is included in the returned string only if value has more than one element.

Values Object[]

An array of objects whose string representations will be concatenated.

Returns String

A string that consists of the elements of values delimited by the separator character. Or Empty if values has zero elements or all the elements of values are null.

Exceptions ArgumentNullException

value is null.

OutOfMemoryException

The length of the resulting string overflows the maximum allowed length (MaxValue).

 

Join(Char, String[])

Concatenates an array of strings, using the specified separator between each member.

public static string Join(char separator, params string[] value);

 Parameters

Separator Char

The character to use as a separator. Separator is included in the returned string only if value has more than one element.

 Value String[]

An array of strings to concatenate.

 

Returns String

A string that consists of the elements of value delimited by the separator character. Empty if value has zero elements or all the elements of value are null.

Exceptions ArgumentNullException

value is null.

 

OutOfMemoryException

The length of the resulting string overflows the maximum allowed length (MaxValue).

 

String Join Method Example

The below code snippet is an example of using the Join() method to append or concatenate all string array elements using specified separator in C#.

 

 static void Main(string[] args)

        {

            string[] sArr = { "Welcome", "to", "CSharp Naija" };

            Console.WriteLine($"Join with Hypen: {string.Join("-", sArr)}");

            string[] sArr1 = { "Musa", "Sule", "Gadabs" };

            Console.WriteLine($"Join with Comma: {string.Join(", ", sArr1)}");

            Console.WriteLine("\nPress Enter Key to Exit..");

            Console.ReadLine();

        }

 

Below is the output screen of the above code

 

Thank you

 

References

1.     Tutlane

2.     MicrosoftDocumentation