VB.NET Trim FunctionUse the Trim Function to remove leading and trailing whitespace from strings.
Trim in VB.NET programs removes leading and trailing whitespace. String data often has leading or trailing whitespace characters—newlines, spaces or tabs.
Characters like spaces at the end or start are usually not needed. With Trim we strip these characters in a declarative way. Other program logic may become simpler.
TrimEnd, TrimStart
First example. This code references a string literal that contains leading spaces and a trailing space. Next the Trim Function is invoked, and a new string is allocated on the managed heap.
Tip The string returned by the Trim Function does not contain the leading spaces or trailing space.
Next To demonstrate, we print out the resulting value with square brackets denoting its first and last character positions.
VB.NET program that uses Trim function
Module Module1 Sub Main() ' Input string. Dim value As String = " This is an example string. " ' Invoke Trim function. value = value.Trim() ' Write output. Console.Write("[") Console.Write(value) Console.WriteLine("]") End Sub End Module
[This is an example string.]
File lines. Text files may have unnecessary spaces or tab characters. If you read in a file line-by-line you can then trim these lines and process them with simpler logic.
VB.NET program that uses Trim on file lines
Imports System.IO Module Module1 Sub Main() ' Read in the lines of a file. For Each line As String In File.ReadAllLines("data.txt") ' The existing line. Console.WriteLine("[{0}]", line) ' Trimmed line. Dim trimmed As String = line.Trim() Console.WriteLine("[{0}]", trimmed) Next End Sub End Module
[ Something] [Something] [Example ] [Example] [ Another] [Another]
Dictionary. A Dictionary can store string keys and reference data objects as values. It is a good idea to trim input before passing it to a Dictionary lookup method.
Tip This ensures that whitespace, which is typically not meaningful in this context, will not disrupt accurate lookups.
A summary. The Trim Function clears excess leading and trailing whitespace characters from string data. With Trim we more easily accept input from users and files.
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