C# remove redundant paths from a list

Question

Say I have this list

List<string> sampleList = new List<string>
{
   "C:\\Folder1",
   "D:\\Folder2",
   "C:\\Folder1\\Folder3",
   "C:\\Folder111\\Folder4"
};

I'd like to remove the paths that are contained in other folders, for example we have C:\Folder1 and C:\Folder1\Folder3

the list's third entry should go away because C:\Folder1 contains C:\Folder1\Folder3

is there something that does that in the .net framework or do i have to write the algo myself?

Answer 1

You should do yourself. Do you think that .net implemented a method to do such a specific task? Use string methods.

Answer 2

Assuming it is not a huge list.

List<string> sampleList = new List<string>
{
   "C:\\Folder1",
   "D:\\Folder2",
   "C:\\Folder1\\Folder3",
   "C:\\Folder111\\Folder4",
   "C:\\Folder1"
};

string sep = Path.DirectorySeparatorChar.ToString();
List<string> shortList = sampleList.Where (l => 
    sampleList.Where(s => 
        l.StartsWith(s + (s.EndsWith(sep) ? String.Empty : sep)) && s != l).Count() == 0
).Distinct().ToList();

Answer 3

I most probably would use string operations on normalized paths strings:

path1 = Path.GetFullPath(path1);
path2 = Path.GetFullPath(path2);

// depending on os, ignore casing, eg by converting to lowercase

if (path1.StartsWith(path2)) 
{
  // ...
}

full example:

var normalizedPaths = sampleList
    .Select(x => Path.GetFullPath(x).ToLowerCase())
    .ToList();

var reducedList = normalizedPaths
    .Distinct()
    .Where(x => !normalizedPaths.Contains(
        y => y.StartsWith(x + Path.DirectorySeparatorChar)
        && x != y));