Why TrimEnd() function of C# behaves like following?

Question

A simple code snippet is as follows:

public static void Main()
{
    string str = "IsRecorded<code>0</code>";
    str = str.TrimEnd("<code>0</code>".ToCharArray());
    Console.WriteLine(str);
}

The output string that I get is IsRecor. Why does the TrimEnd function strips of ded from the string when it is supposed to strip only <code>0</code>. Also if I reduce the str to IsRec then it gives IsR as output. Why is this happening?

Your .ToCharArray specify that you want to delete all content after every char in your string. So d is in your String, so it cut after it. — KiwiJaune, Apr 23 '19 at 12:45
If you want the moral equivalent of "cut off this string, but only if it occurs at the end", you could use `Regex.Replace("IsRecorded0", Regex.Escape("0") + "$", "")`. (There are more efficient alternatives, but something something premature optimization.) — Jeroen Mostert, Apr 23 '19 at 12:48
Possible duplicate of [Strange TrimEnd behaviour with \ char](https://stackoverflow.com/questions/5700903/strange-trimend-behaviour-with-char) — Igor, Apr 23 '19 at 12:48

Jon Skeet · Accepted Answer · 2019-04-23T12:57:19.413

The parameter for TrimEnd specifies the set of characters to be trimmed. It's not meant to be a suffix to be trimmed.

So you're saying you want to trim any character in the set { '<', 'c', 'o', 'd', 'e', '>', '0', '/' }. The letters "ded" are all in that set, so they're being trimmed.

If you want to remove a suffix, don't use TrimEnd. Use something like this:

public static string RemoveSuffix(string input, string suffix) =>
    input.EndsWith(suffix, StringComparison.Ordinal)
        ? input.Substring(0, input.Length - suffix.Length)
        : input;

(The string comparison part is important to avoid "interesting" culture-specific effects in some cases. It basically does the simplest match possible.)

Prasad Telkikar · Answer 2 · 2019-04-23T12:57:36.223

1

You can use .LastIndexOf() & Remove() to remove string which is at the end

string str = "IsRecorded<code>0</code>";
str = str.Remove(str.LastIndexOf("<code>0</code>"));

.LastIndexOf(string param) : This will find index of last occurrence of specified string.

.Remove(int startIndex) : Remove string from given index

edited Apr 23 '19 at 12:57

answered Apr 23 '19 at 12:50

Prasad Telkikar

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score 0 · Answer 3 · answered Apr 23 '19 at 12:46

0

Try this instead :

        string str = "IsRecorded<code>0</code>";
        str = str.Substring(0, str.IndexOf("<code>0</code>"));
        Console.WriteLine(str);

answered Apr 23 '19 at 12:46

KiwiJaune

530
2
16

Note that if "0" occurs more than once in the string, that will remove everything before the *first* of them. That may or may not be what's desired... – Jon Skeet Apr 23 '19 at 12:47
Sure, it's not a final solution, just a simple way to do what he thinked TrimEnd does. Your solution is more flexible. – KiwiJaune Apr 23 '19 at 12:50

score 0 · Answer 4 · answered Apr 23 '19 at 12:52

0

Another solution could be:

string str = "IsRecorded<code>0</code>";
str = str.Replace("<code>0</code>", "");
Console.WriteLine(str);

PS: I know that wont trim just the end part, but if it's not a problem then it could be used

answered Apr 23 '19 at 12:52

Eduardo Gadotti

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Why TrimEnd() function of C# behaves like following?

4 Answers4