How can I join an array of strings but first remove the elements of the array that are empty?

Question

I am using the following:

return string.Join(\"\\n\", parts);

Parts has 7 entries but two of them are the empty string \"\". How can I fi

Answer 1

Try it using LINQ

string[] hello = new string[] { "ads", "zxc", "wer", "", "wer", "", "243" };
string newString = string.Join("\n", hello.Where(x => x.Trim().Length != 0));
MessageBox.Show(newString);

or

return string.Join("\n", hello.Where(x => x.Trim().Length != 0));

Answer 2

To do it in .NET 2.0 (no LINQ), e.g. for ReportingServices without writing a function for it:

C#

string a = "", b = "b", c = "", d = "d", e = "";
string lala = string.Join(" / ",
    string.Join("\u0008", new string[] { a, b, c, d, e }).Split(new char[] { '\u0008' }, System.StringSplitOptions.RemoveEmptyEntries)
);

System.Console.WriteLine(lala);

VB.NET

Dim a As String = "", b As String = "b", c As String = "", d As String = "d", e As String = ""
Dim lala As String = String.Join(" / ", String.Join(vbBack, New String() {a, b, c, d, e}).Split(New Char() {ControlChars.Back}, System.StringSplitOptions.RemoveEmptyEntries))

System.Console.WriteLine(lala)

This assumes that the character backspace doesn't occur in your strings (should usually be true, because you can't simply enter this character by keyboard).

Answer 3

An alternate way of doing this is by using StringSplitOptions.RemoveEmptyEntries:

e.g.

string yourString = "The|quick||brown|||fox|is|here";
char[] delimiter = new char[] { '|' };

string result = string.Join(",", yourString.Split(delimiter, StringSplitOptions.RemoveEmptyEntries));

This gives:

The,quick,brown,fox,is,here

@Stefan Steiger:

string yourString = "echo 'foo' | sed '/foo/d;'";

This gives:

echo 'foo' , sed '/foo/d;'

Which is as I would expect. See the dotnetfiddle of it.

Answer 4

You can use Where in LINQ to select strings which are not empty:

 return string.Join("\n", parts.Where(s => !string.IsNullOrEmpty(s)));