Convert multi-dimensional collection to string with separator

Question

As I was working on this answer, I've written some code to convert a generic multi-dimensional collection to a string.

public static string ConvertToString<T>(this IEnumerable<IEnumerable<T>> input, string columnSplit = "", string rowSplit = "\n")
{
    return string.Join(rowSplit, input.Select(r => string.Concat(string.Join(columnSplit, r.Select(c => c.ToString())))));
}

Example Input

IEnumerable<IEnumerable<string>> input = new List<List<string>>
{
    new List<string> { "R", "L", "R", "R" },
    new List<string> { "L", "R", "V", "R" },
    new List<string> { "L", "R", "V", "R" },
    new List<string> { "R", "L", "L", "R" },
};

Desired Output

RLRR
LRVR
LRVR
RLLR

Although the code works, I don't find the solution to be elegant with the fact that it requires a string.Join inside a string.Concat inside a Select. Is there a way to simplify this solution.

Why you're wrapping Join with Concat? Looks like redundancy. — aepot, Aug 03 '20 at 22:56
When I do `string.Concat(columnSplit, r.Select(c => c.ToString()))`, it only joins the `columnSplit` once, then returns Enumerable ToString, which isn't what I wanted. — Hayden, Aug 03 '20 at 22:58
@aepot After looking at Keith's answer, I now realise my mistake. Thanks for pointing it out. — Hayden, Aug 03 '20 at 23:01

Keith Nicholas · Accepted Answer · 2020-08-03T23:01:55.767

this will work without the concat and the select....

public static string ConvertToString<T>(this IEnumerable<IEnumerable<T>> input, string columnSplit = "", string rowSplit = "\n")
{
  return string.Join(rowSplit, input.Select(r => string.Join(columnSplit, r)));
}

works with:

 IEnumerable<IEnumerable<string>> input = new List<List<string>>
            {
                new List<string> { "R", "L", "R", "R" },
                new List<string> { "L", "R", "V", "R" },
                new List<string> { "L", "R", "V", "R" },
                new List<string> { "R", "L", "L", "R" },
            };

and:

 IEnumerable<IEnumerable<int>> nums = new List<List<int>>
            {
                new List<int> { 1,2,3,4},
                new List<int> { 5,6,7,8},
            };

I don't know why I didn't do this in the first place, seems dumb that I missed it. Thanks for your answer. — Hayden, Aug 03 '20 at 23:01

score 1 · Answer 2 · answered Aug 03 '20 at 23:04

Since you're defining extensions anyway, why not go all the way?

public static string ConvertToString<T>(this IEnumerable<IEnumerable<T>> input, string columnSplit = "", string rowSplit = "\n") =>
    input.Select(r => r.ConvertToString(columnSplit)).ConvertToString(rowSplit);
    
public static string ConvertToString<T>(this IEnumerable<T> input, string split = "") => 
    string.Join(split, input.Select(i => i.ToString()));

score 0 · Answer 3 · answered Aug 04 '20 at 00:27

These are some nasty methods I did

public static string ToStringEnumeration(this IEnumerable source)
{
    return ToStringEnumeration(source, EnumerationMode.NewLineEach, null);
}

public enum EnumerationMode
{
    NewLineEach,
    Separator,
}

public static string ToStringEnumeration(this IEnumerable source, EnumerationMode mode, string separator = null)
{
    return ToStringEnumeration(source, mode, separator, null, null);
}

public static string ToStringEnumeration(this IEnumerable source, EnumerationMode mode, string separator, IFormatProvider provider, string format)
{
    if (source is null)
        throw new ArgumentNullException(nameof(source));

    if (source.IsEmpty())
        return "";

    var sBuilder = new StringBuilder();
    foreach (var element in source)
    {
        var strElement = format is null ? element.ToString() : string.Format(provider, format, element);
        sBuilder.Append(strElement);

        if (mode == EnumerationMode.NewLineEach)
            sBuilder.AppendLine();
        else if (mode == EnumerationMode.Separator)
            sBuilder.Append(separator);
    }

    var sLength = separator?.Length ?? 1;

    if (mode == EnumerationMode.NewLineEach) //quit /n/r
        sBuilder.Remove(sBuilder.Length - 2, 2);
    else if (mode == EnumerationMode.Separator)
        sBuilder.Remove(sBuilder.Length - sLength, sLength);

    return sBuilder.ToString();
}

Convert multi-dimensional collection to string with separator

3 Answers3

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