Trim last character from a string

I have a string say

"Hello! world!" 

I want to do a trim or a remove to take out the ! off world but not off Hello.

"Hello! world!".TrimEnd('!');

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EDIT:

What I've noticed in this type of questions that quite everyone suggest to remove the last char of given string. But this does not fulfill the definition of Trim method.

> Trim - Removes all occurrences of > white space characters from the > beginning and end of this instance.

MSDN-Trim

Under this definition removing only last character from string is bad solution.

So if we want to "Trim last character from string" we should do something like this

Example as extension method:

public static class MyExtensions
{
  public static string TrimLastCharacter(this String str)
  {
     if(String.IsNullOrEmpty(str)){
        return str;
     } else {
        return str.TrimEnd(str[str.Length - 1]);
     }
  }
}

Note if you want to remove all characters of the same value i.e(!!!!)the method above removes all existences of '!' from the end of the string, but if you want to remove only the last character you should use this :

else { return str.Remove(str.Length - 1); }

String withoutLast = yourString.Substring(0,(yourString.Length - 1));

if (yourString.Length > 1)
    withoutLast = yourString.Substring(0, yourString.Length - 1);

or

if (yourString.Length > 1)
    withoutLast = yourString.TrimEnd().Substring(0, yourString.Length - 1);

...in case you want to remove a non-whitespace character from the end.

string s1 = "Hello! world!";
string s2 = s1.Trim('!');

The another example of trimming last character from a string:

string outputText = inputText.Remove(inputText.Length - 1, 1);

You can put it into an extension method and prevent it from null string, etc.

Try this:

return( (str).Remove(str.Length-1) );

string helloOriginal = "Hello! World!";
string newString = helloOriginal.Substring(0,helloOriginal.LastIndexOf('!'));

In .NET 5 / C# 8:

You can write the code marked as the answer as:

public static class StringExtensions
{
    public static string TrimLastCharacters(this string str) => string.IsNullOrEmpty(str) ? str : str.TrimEnd(str[^1]);
}

However, as mentioned in the answer, this removes all occurrences of that last character. If you only want to remove the last character you should instead do:

    public static string RemoveLastCharacter(this string str) => string.IsNullOrEmpty(str) ? str : str[..^1];

A quick explanation for the new stuff in C# 8:

The ^ is called the "index from end operator". The .. is called the "range operator". ^1 is a shortcut for arr.length - 1. You can get all items after the first character of an array with arr[1..] or all items before the last with arr[..^1]. These are just a few quick examples. For more information, see https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-8, "Indices and ranges" section.

string s1 = "Hello! world!"
string s2 = s1.Substring(0, s1.Length - 1);
Console.WriteLine(s1);
Console.WriteLine(s2);

Very easy and simple: > str = str.Remove( str.Length - 1 );

you could also use this:

public static class Extensions
 {
        
        public static string RemovePrefix(this string o, string prefix)
        {
            if (prefix == null) return o;
            return !o.StartsWith(prefix) ? o : o.Remove(0, prefix.Length);
        }
        
        public static string RemoveSuffix(this string o, string suffix)
        {
            if(suffix == null) return o;
            return !o.EndsWith(suffix) ? o : o.Remove(o.Length - suffix.Length, suffix.Length);
        }
    
    }

An example Extension class to simplify this: -

internal static class String
{
    public static string TrimEndsCharacter(this string target, char character) => target?.TrimLeadingCharacter(character).TrimTrailingCharacter(character);
    public static string TrimLeadingCharacter(this string target, char character) => Match(target?.Substring(0, 1), character) ? target.Remove(0,1) : target;
    public static string TrimTrailingCharacter(this string target, char character) => Match(target?.Substring(target.Length - 1, 1), character) ? target.Substring(0, target.Length - 1) : target;

    private static bool Match(string value, char character) => !string.IsNullOrEmpty(value) && value[0] == character;
}

Usage

"!Something!".TrimLeadingCharacter('X'); // Result '!Something!' (No Change)
"!Something!".TrimTrailingCharacter('S'); // Result '!Something!' (No Change)
"!Something!".TrimEndsCharacter('g'); // Result '!Something!' (No Change)

"!Something!".TrimLeadingCharacter('!'); // Result 'Something!' (1st Character removed)
"!Something!".TrimTrailingCharacter('!'); // Result '!Something' (Last Character removed)
"!Something!".TrimEndsCharacter('!'); // Result 'Something'  (End Characters removed)

"!!Something!!".TrimLeadingCharacter('!'); // Result '!Something!!' (Only 1st instance removed)
"!!Something!!".TrimTrailingCharacter('!'); // Result '!!Something!' (Only Last instance removed)
"!!Something!!".TrimEndsCharacter('!'); // Result '!Something!'  (Only End instances removed)

Slightly modified version of @Damian Leszczyński - Vash that will make sure that only a specific character will be removed.

public static class StringExtensions
{
    public static string TrimLastCharacter(this string str, char character)
    {
        if (string.IsNullOrEmpty(str) || str[str.Length - 1] != character)
        {
            return str;
        }
        return str.Substring(0, str.Length - 1);
    }
}

I took the path of writing an extension using the TrimEnd just because I was already using it inline and was happy with it... i.e.:

static class Extensions
{
        public static string RemoveLastChars(this String text, string suffix)
        {            
            char[] trailingChars = suffix.ToCharArray();

            if (suffix == null) return text;
            return text.TrimEnd(trailingChars);
        }

}

Make sure you include the namespace in your classes using the static class ;P and usage is:

string _ManagedLocationsOLAP = string.Empty;
_ManagedLocationsOLAP = _validManagedLocationIDs.RemoveLastChars(",");          

If you want to remove the '!' character from a specific expression("world" in your case), then you can use this regular expression

string input = "Hello! world!";

string output = Regex.Replace(input, "(world)!", "$1", RegexOptions.Multiline | RegexOptions.Singleline);

// result: "Hello! world"

the $1 special character contains all the matching "world" expressions, and it is used to replace the original "world!" expression