Recipe 2.23 Pruning Characters from the Headand/or Tail of a String

Problem

You have a string with a specific set of characters, such as spaces, tabs, escaped single/double quotes, any type of punctuation character(s), or some other character(s), at the beginning and/or end of a string. You want a simple way to remove these characters.

Solution

Use the Trim, TrimEnd, or TrimStart instance methods of the String class:

string foo = "--TEST--";
Console.WriteLine(foo.Trim(new char[1] {'-'}));            // Displays "TEST"

foo = ",-TEST-,-";
Console.WriteLine(foo.Trim(new char[2] {'-',','}));        // Displays "TEST"

foo = "--TEST--";
Console.WriteLine(foo.TrimStart(new char[1] {'-'}));       // Displays "TEST--"

foo = ",-TEST-,-";
Console.WriteLine(foo.TrimStart(new char[2] {'-',','}));   // Displays "TEST-,-"

foo = "--TEST--";
Console.WriteLine(foo.TrimEnd(new char[1] {'-'}));         // Displays "--TEST"

foo = ",-TEST-,-";
Console.WriteLine(foo.TrimEnd(new char[2] {'-',','}));     // Displays "-,-TEST"

Discussion

The Trim method is most often used to eliminate whitespace at the beginning and end of a string. In fact, if you call Trim without any parameters on a string variable, this is exactly what would happen. The Trim method is overloaded to allow you to remove other types of characters from the beginning and end of a string. You can pass in a char[] containing all the characters that you want removed from the beginning and end of a string. Note that if the characters contained in this char[] are located somewhere in the middle of the string, they are not removed.

The TrimStart and TrimEnd methods remove characters at the beginning and end of a string, respectively. These two methods are not overloaded, similar to the Trim method. Rather, these two methods accept only a char[]. If you pass a null into either one of these methods, only whitespace is removed from the beginning or the end of a string.

See Also

See the "String.Trim Method," "String.TrimStart Method," and "String.TrimEnd Method" topics in the MSDN documentation.