Char Array Dictionary String ToTitleCase

Uppercase first

This Function uppercases the first letter. It acts upon a VB.NET String. The value "test" becomes "Test". None of the other characters should be modified.

If the first character is whitespace or a digit, it should not be affected. We introduce a custom method that uppercases the first letter.

Example

UppercaseFirstLetter receives a String and returns a String. In this function, we first test for null or empty parameters, and exit early in this case.

Next We call ToCharArray to convert the String into a mutable array of characters.

Then We use Char.ToUpper to uppercase the first letter, and we finally return a String instance built from the character array.

Module Module1

    Sub Main()
        Console.WriteLine(UppercaseFirstLetter("sam"))
        Console.WriteLine(UppercaseFirstLetter("perls"))
        Console.WriteLine(UppercaseFirstLetter(Nothing))
        Console.WriteLine(UppercaseFirstLetter("VB.NET"))
    End Sub

    Function UppercaseFirstLetter(ByVal val As String) As String
        ' Test for nothing or empty.
        If String.IsNullOrEmpty(val) Then
            Return val
        End If

        ' Convert to character array.
        Dim array() As Char = val.ToCharArray

        ' Uppercase first character.
        array(0) = Char.ToUpper(array(0))

        ' Return new string.
        Return New String(array)
    End Function

End ModuleSam
Perls

VB.NET

Function notes

This function, which uses the ToCharArray constructor, avoids allocations. In performance analysis, eliminating string allocations is often a clear win.

Warning This function has a limitation. It won't correctly process names that have multiple uppercase letters in them.

`ToTitleCase`

Instead of this custom implementation, you could use the ToTitleCase function. With ToTitleCase, every word is capitalized—this is a slightly different behavior.

We learned one way you can uppercase only part of a string, such as the first letter. This method could be used to clean up poorly formatted character data.