Best way to split string by last occurrence of character?
C#StringSplitC# Problem Overview
Let's say I need to split string like this:
Input string: "My. name. is Bond._James Bond!" Output 2 strings:
- "My. name. is Bond"
- "_James Bond!"
I tried this:
int lastDotIndex = inputString.LastIndexOf(".", System.StringComparison.Ordinal);
string firstPart = inputString.Remove(lastDotIndex);
string secondPart= inputString.Substring(lastDotIndex + 1, inputString.Length - firstPart.Length - 1);
Can someone propose more elegant way?
C# Solutions
Solution 1 - C#
Updated Answer (for C# 8 and above)
C# 8 introduced a new feature called ranges and indices, which offer a more concise syntax for working with strings.
string s = "My. name. is Bond._James Bond!";
int idx = s.LastIndexOf('.');
if (idx != -1)
{
Console.WriteLine(s[..idx]); // "My. name. is Bond"
Console.WriteLine(s[(idx + 1)..]); // "_James Bond!"
}
Original Answer (for C# 7 and below)
This is the original answer that uses the string.Substring(int, int)
method. It's still OK to use this method if you prefer.
string s = "My. name. is Bond._James Bond!";
int idx = s.LastIndexOf('.');
if (idx != -1)
{
Console.WriteLine(s.Substring(0, idx)); // "My. name. is Bond"
Console.WriteLine(s.Substring(idx + 1)); // "_James Bond!"
}
Solution 2 - C#
You can also use a little bit of LINQ. The first part is a little verbose, but the last part is pretty concise :
string input = "My. name. is Bond._James Bond!";
string[] split = input.Split('.');
string firstPart = string.Join(".", split.Take(split.Length - 1)); //My. name. is Bond
string lastPart = split.Last(); //_James Bond!
Solution 3 - C#
string[] theSplit = inputString.Split('_'); // split at underscore
string firstPart = theSplit[0]; // get the first part
string secondPart = "_" + theSplit[1]; // get the second part and concatenate the underscore to at the front
EDIT: Following from the comments; this only works if you have one instance of the underscore character in your input string.
Solution 4 - C#
-
Assuming you only want the split character to appear on the second and greater split strings...
-
Assuming you want to ignore duplicate split characters...
-
More curly braces... check...
-
More elegant... maybe...
-
More fun... Heck yeah!!
var s = "My. name. is Bond._James Bond!"; var firstSplit = true; var splitChar = '_'; var splitStrings = s.Split(new[] { splitChar }, StringSplitOptions.RemoveEmptyEntries) .Select(x => { if (!firstSplit) { return splitChar + x; } firstSplit = false; return x; });