C# String TrimStart

Summary: in this tutorial, you will learn how to use the C# String TrimStart() method to remove all the leading white-space characters from a string.

Introduction to the C# String TrimStart() method

The String TrimStart() method allows you to remove all the leading white-space characters from a string. It returns a new string with the leading white spaces removed.

Here’s the syntax of the TrimStart() method:

public string TrimStart();Code language: C# (cs)

The following example shows how to use the TrimStart() method to remove the leading white spaces from the string " Hello, World!";

using static System.Console;

var message = " Hello, World!";
var trimmed = message.TrimStart();

WriteLine(message);
WriteLine(trimmed);Code language: C# (cs)

Output:

 Hello, World!
Hello, World!Code language: C# (cs)

In this example, the message string contains leading white spaces. We call the TrimStart() method on the message string. The method returns a result string (trimmed) that has the leading white spaces removed.

Note that the TrimStart() method doesn’t change the original string but returns a new string.

The Unicode standard defines white-space characters. The TrimStart() method removes any leading and trailing characters that, when passed to the Char.IsWhiteSpace() method, returns true:

public static bool IsWhiteSpace (char c);Code language: C# (cs)

Using C# String TrimStart() to remove the leading instances of a character

The String TrimStart() method has an overload that allows you to remove the leading instances of a character from the current string:

public string TrimStart(char trimChar);Code language: C# (cs)

In this syntax, the trimChar is a character to remove. The TrimStart() method returns a new string with the all the leading trimChar removed.

For example, the following program uses the TrimStart() method to remove the leading (/) from a string:

using static System.Console;

var comment = "//This is a in C#";
var result = comment.TrimStart('/');

WriteLine(comment);
WriteLine(result);Code language: C# (cs)

Output:

//This is a comment in C#
This is a comment in C#Code language: C# (cs)

Using C# String TrimStart() to remove the leading occurrences of a set of characters

The String TrimStart() method has an overload that removes any leading and trailing instances of specified characters from the current string:

public string TrimStart (
   params char[]? trimChars
);Code language: C# (cs)

In this syntax, the trimChars is an array of characters to remove. Note that if the trimChars is null, the TrimStart() method returns a new string with the leading white spaces removed.

The following example uses the TrimStart() method to remove the leading characters / and spaces from a string:

using static System.Console;

var comment = "// This is a comment in C#";
char[] trimChars = { '/', ' ' };
var result = comment.TrimStart(trimChars);

WriteLine(comment);
WriteLine(result);Code language: C# (cs)

Output:

// This is a comment in C#
This is a comment in C#Code language: C# (cs)

Summary

Use the C# String TrimStart() method to remove all the leading white spaces or a set of specified characters from a string.

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