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VB.NET String.Compare ExamplesUse String.Compare, String.CompareOrdinal and CompareTo to determine the ordering of strings.
String.Compare. In VB.NET, 2 Strings can be compared. With Compare, CompareOrdinal, and CompareTo, we can determine whether one String is ordered before another String.
Function info. Compare is used to implement sorting routines. Compare returns just three values: -1, 0 and 1. This number indicates the relation of the two strings being compared.
Sort
Example. First we declare two String local variables. Next we call the Shared String.Compare function. It returns -1. This means that String a is smaller than, or comes before, String b.
Next The result of 1 indicates that String "b" is larger than String a. And 0 means the two Strings are equal.
CompareOrdinal This treats each character as an ordinal value. This means Chars are treated by their numeric value.
CompareTo With CompareTo, we use String instances to perform the comparison. The results are the same as for String.Compare.
Console
VB.NET program that uses compare functions
Module Module1 Sub Main() Dim a As String = "a" Dim b As String = "b" Dim c As Integer = String.Compare(a, b) Console.WriteLine(c) c = String.CompareOrdinal(b, a) Console.WriteLine(c) c = a.CompareTo(b) Console.WriteLine(c) c = b.CompareTo(a) Console.WriteLine(c) c = "x".CompareTo("x") Console.WriteLine(c) End Sub End Module
-1 1 -1 1 0
Discussion. In a sort, each String must be compared to other Strings. With Compare and CompareTo, an Enum of StringComparison type can be specified as an argument.
And Internally, those methods will use a Compare method based on the Enum argument.
Enum
So StringComparison.Ordinal will result in the CompareOrdinal method being used in some way.
LastIndexOf
Summary. With these methods, if the first String is ordered first, we receive the value -1. If the Strings are equal, we receive 0. And we receive 1 if the second String is first.
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