Building a new path-like string from an existing one
You can do this quite tersely with Regex
var newFolder = Regex.Replace(folder, @"\.", @"\$`.");
This matches on each period. Each time it finds a period, it inserts a backslash and then the entire input string before the match ($`
). We have to add the period in again at the end.
So, steps are (< and > indicate text inserted by the substitution at that step):
- Match on the 1st period.
one<\one>.two.three
- Match on the 2nd period.
one\one.two<\one.two>.three
- Result:
one\one.two\one.two.three
For bonus points, use Path.DirectorySeparatorChar
for cross-platform correctness.
var newFolder = Regex.Replace(folder, @"\.", $"{Path.DirectorySeparatorChar}$`.")
Here's another linqy way:
var a = "";
var newFolder = Path.Combine(folder.Split('.')
.Select(x => a += (a == "" ? "" : ".") + x).ToArray());
You can try Linq:
string folder = "one.two.three";
string[] parts = folder.Split('.');
string result = Path.Combine(Enumerable
.Range(1, parts.Length)
.Select(i => string.Join(".", parts.Take(i)))
.ToArray());
Console.Write(newFolder);
Outcome:
one\one.two\one.two.three
You can go forward-only in one loop like this:
var folder = "one.two.three";
var newFolder = new StringBuilder();
int index = -1;
while (index + 1 < folder.Length) {
index = folder.IndexOf('.', index + 1);
if (index < 0) {
newFolder.Append(folder);
break;
}
else {
newFolder.Append(folder, 0, index);
newFolder.Append(Path.DirectorySeparatorChar);
}
}
You can try it out here.