Join with intelligent separators

Question

It's easy enough to write, of course, but in C# 2010, is there a built-in Join (or similar) method that will only add a separator if both the previous and next elements are non-null and non-empty?

In other words SmartJoin(", ","Hood","Robin") would produce "Hood, Robin" but SmartJoin(", ", "Robin Hood", string.Empty) would produce simply "Robin Hood".

What is the output of `SmartJoin(", ", "First", String.Empty, "Second")`? — jason, Jul 13 '11 at 19:42
In that case, it should be "First, Second". Sorry, my wording was misleading there...I was thinking only of a two-item list. — , Jul 13 '11 at 19:57

score 5 · Answer 1 · answered Jul 13 '11 at 19:43

5

How about this:

public void SmartJoin(string separator, params string[] Items)
{
   String.Join(separator, Items.Where(x=>!String.IsNullOrEmpty(x)).ToArray());
}

answered Jul 13 '11 at 19:43

CodingGorilla

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The question was not to implement it, but to point to existing framework method that does that. – NOtherDev Jul 13 '11 at 19:47
1

Good point, again my reading skills have failed me today. I think it's time for a nap! – CodingGorilla Jul 13 '11 at 19:49

score 1 · Accepted Answer · answered Jul 13 '11 at 19:44

1

There is no built-in join which you need.

answered Jul 13 '11 at 19:44

Kirill Polishchuk

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Thanks, that's what I thought. – Jul 13 '11 at 19:56

score 0 · Answer 3 · answered Jul 28 '13 at 18:42

NotherDev was right, strictly speaking, there is no such method build in, but still @CodingGorila solution helped me, and should be added to the next .NET version by my account, though I did still turn it into a static function and have it return a string to make it work in my situation:

public static string SmartJoin(string separator, params string[] Items) {
    return String.Join(separator, Items.Where(x=>!String.IsNullOrEmpty(x)).ToArray());
}

score 0 · Answer 4 · answered Jul 28 '13 at 18:51

NotherDev was right, strictly speaking, there is no such method build in, but still @CodingGorila solution helped me, and should be added to the next .NET version by my account, though I did still turn it into a static function and have it return a string to make it work in my situation:

public static string SmartJoin(string separator, params string[] Items) {
    return String.Join(separator, Items.Where(x=>!String.IsNullOrEmpty(x)));
}

score 0 · Answer 5 · answered Jul 14 '11 at 05:22

Here's another way using "aggregate" method of linq

string result = new List<string>() { "Hood", "Robin" }.Aggregate(SmartJoin());
string result2 = new List<string>() { "Robin Hood", "" }.Aggregate(SmartJoin());

private static Func<string, string, string> SmartJoin()
{
  return (x, y) => x + (string.IsNullOrEmpty(y) ? "" : ", " + y);
}

Join with intelligent separators

5 Answers5

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