System.Text.RegularExpressions.Regex.IsMatch(input, "\d")So times you will need to check a string, to see if it contains a number.
What’s the best way to do this?
There are several solutions like this function :
TryParse approach:
Public Shared Function IsNumeric(Expression As Object) As Boolean
Dim isNum As Boolean
Dim retNum As Double
isNum = [Double].TryParse(Convert.ToString(Expression), System.Globalization.NumberStyles.Any, System.Globalization.NumberFormatInfo.InvariantInfo, retNum) Return isNumEnd Function
Check Characters in String approach:
Public NotInheritable Class Extensions
Private Sub New()
End Sub
<System.Runtime.CompilerServices.Extension> _
Public Shared Function IsNumeric(s As String) As Boolean
For Each c As Char In s
If Not Char.IsDigit(c) AndAlso c <> "."C Then
Return False
End If
NextReturn True
End Function
End Class
What about locales where '.' is the group separator, not the comma (e.g. pt-Br)? What about negative numbers?
Group separators (commas in English)? Currency symbols?
TryParse() can manage all of these as required using NumberStyles and IFormatProvider.
Regular Expressions approach:
System.Text.RegularExpressions.Regex.IsMatch(input, "^\d+$")This will return true if input is all numbers
If you just want to know if it has one or more numbers mixed in with characters, leave off the ^ + and$.
System.Text.RegularExpressions.Regex.IsMatch(input, @"\d")Actually I think it is better than TryParse because a very long string could potentially overflow TryParse.
Summary
In my opinion the winner is the Regular Expressions Method
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