Optimal Environment.Newline in interpolated string

Question

I wanted to insert multiple new lines in a string so I used an interpolated string as my choice of a format mechanism which should be pretty fast.

Example:

string mystring = $"one line{Environment.NewLine}{Environment.NewLine}{Environment.NewLine}another line{Environment.NewLine}end";

Now that works but how can I better insert multiple Environment.Newline in an interpolated string; for example if I wanted 15 this gets cumbersome.

I am aware of string.Replace(, string.Format(), and concatenation Environment.NewLine + Environment.NewLine + Environment.NewLine as well as literal string @"stuff" with blank lines however is not the question (an alternative) but rather how to insert multiples such my fake example of

string mystring = $"one line{Environment.NewLine(3)}another line{Environment.NewLine}end text";

Rufus L · Answer 1 · 2019-01-07T19:30:40.203

2

You could write a simple helper method to get a repeated string, and then call that:

static string Repeat(string input, int count)
{
    var result = new StringBuilder();
    for (var i = 0; i < count; i++) result.Append(input);
    return result.ToString();
}

string mystring = 
    $"one line{Repeat(Environment.NewLine, 3)}another line{Environment.NewLine}end";

And if you don't want to explicitly call another function, you could write an extension method:

public static class Extensions
{
    public static string Repeat(this string input, int count)
    {
        if (input == null) return null;
        if (count < 1) return string.Empty;
        var result = new StringBuilder();
        for (var i = 0; i < count; i++) result.Append(input);
        return result.ToString();
    }
}

And then the syntax is simpler:

string mystring = 
    $"one line{Environment.NewLine.Repeat(3)}another line{Environment.NewLine}end";

edited Jan 07 '19 at 19:30

answered Jan 07 '19 at 19:16

Rufus L

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Noted in question I know about this option, thanks – Mark Schultheiss Jan 07 '19 at 19:24
Updated answer. – Rufus L Jan 07 '19 at 19:27
One reason is to optimize for a highly performance driven application thus creating a `StringBuilder` or doing a loop, calling a custom method etc. is/was not an option considered. Thanks for posting however as it may fit someone else's circumstance. – Mark Schultheiss Jan 07 '19 at 19:29
1

I'm pretty sure that any solution that takes a string and a count is going to use a loop behind the scenes. I.e. [`Enumerable.Repeat`](https://github.com/dotnet/corefx/blob/master/src/System.Linq/src/System/Linq/Repeat.cs), and [`StringBuilder.Insert`](https://referencesource.microsoft.com/#mscorlib/system/text/stringbuilder.cs,4fc7620ab6118309). For performance, I guess you want something that resolves at compile time. Not sure about that one. – Rufus L Jan 07 '19 at 19:40

score 2 · Answer 2 · answered Jan 07 '19 at 19:36

2

Linq can do this:

var fifteenNewlines = string.Concat(Enumerable.Repeat(Environment.NewLine, 15));

answered Jan 07 '19 at 19:36

Dour High Arch

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2

I see this answer was [already given in a duplicate](https://stackoverflow.com/a/53816447/22437). – Dour High Arch Jan 07 '19 at 19:40

score 1 · Accepted Answer · answered Jan 07 '19 at 19:33

Maybe not the most elegant solution, but you can call a method from within an interpolated string. The method can return a specified number of new lines.

private string NewLines(int lines)
{           
 return new StringBuilder().Insert(0,$"{Environment.NewLine}, lines").ToString();
}

Then just call

string mystring = $"one line{NewLines(3)}another line{NewLines(1)}end text";

Optimal Environment.Newline in interpolated string

3 Answers3