TrimEnd, TrimStartIn C# TrimEnd removes ending characters from a string. Suppose we have a string with trailing punctuation. We can use TrimEnd to remove these characters.
Meanwhile, TrimStart removes from the start of a string. These methods are useful, and their effects are simple—they return copied strings.
TrimEndThis program loops through an array and trims it sending characters with TrimEnd. We use a string array. The results are printed to the screen.
string array "items" here is used to show the results of TrimEnd. The TrimEnd method itself receives chars, not strings.string array. Each string in the array is looped over with the foreach-loop.TrimEnd is called. It removes the question mark, period and comma from the string.using System;
// Our example string array.
string[] items = new string[]
{
"test?",
"ok..."
};
// Loop and call TrimEnd.
foreach (string item in items)
{
string trimmed = item.TrimEnd('?', '.', ',');
Console.WriteLine(item);
Console.WriteLine(trimmed);
}test?
test
ok...
okTrimStartTrimStart removes leading characters. Sometimes strings have starting characters that are not needed. TrimStart removes as many characters of the specific values as required.
TrimStart, which contains the characters you want to Trim.using System;
// Trim this string.
string text = "\t, again and again.";
// Trim these characters.
char[] array = new char[] { '\t', ',', ' ' };
text = text.TrimStart(array);
Console.WriteLine(text);again and again.Custom implementations of TrimEnd are faster than the version included in .NET. You can use a for-loop from the last index of the string.
TrimTrailingChars, an optimized method. In the method, we count characters, and call Substring().TrimEnd with a parameter array cached as a local variable. This avoids an allocation on each call.TrimTrailingChars still performs faster than TrimEnd, but TrimEnd is faster than before.using System;
using System.Diagnostics;
class Program
{
static string TrimTrailingChars(string value)
{
int removeLength = 0;
for (int i = value.Length - 1; i >= 0; i--)
{
char let = value[i];
if (let == '?' || let == '!' || let == '.')
{
removeLength++;
}
else
{
break;
}
}
if (removeLength > 0)
{
return value.Substring(0, value.Length - removeLength);
}
return value;
}
const int _max = 10000000;
static void Main()
{
var paramArray = new char[] { '?', '!', '.' };
var s1 = Stopwatch.StartNew();
// Version 1: use optimized method.
for (int i = 0; i < _max; i++)
{
var result = TrimTrailingChars("hello!?");
if (result == null)
{
return;
}
}
s1.Stop();
var s2 = Stopwatch.StartNew();
// Version 2: use TrimEnd.
for (int i = 0; i < _max; i++)
{
var result = "hello!?".TrimEnd(paramArray);
if (result == null)
{
return;
}
}
s2.Stop();
Console.WriteLine(((double)(s1.Elapsed.TotalMilliseconds * 1000000) / _max).ToString("0.00 ns"));
Console.WriteLine(((double)(s2.Elapsed.TotalMilliseconds * 1000000) / _max).ToString("0.00 ns"));
}
}13.54 ns Optimized method
15.85 ns TrimEndTrimEnd and TrimStart can be used with array parameters. They remove chars from the end and start of strings. They remove all characters specified until they can't remove one.