Question

I would like to validate and extract the hours and minutes from a string using Regex in .NET.
Just to recuperate the two numbers, separated(or not) by :. Accepted format
h:m or m. Unaccepted :m, h:.

EDIT:
This is to note, that the number of hours could overflow the 23 till… 32.

The overflow for hours(over 32) and minutes(over 59) I will do after values recuperation(int.Parse)

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_{* just for fun maybe there a a relative simple regex that could filter also the >32 for hour and >59 for minute (for minutes it could be [0-5]*[0-9], for hours I don’t know)?}

Answer 1

Finally, the code for validating (till 32) and also obtaining values is(vb.net version):

Dim regexHour As New Regex( _ 
   "((?<hours>([012]?\d)|(3[01]))\:)?(?<minutes>[0-5]?\d)", _
    RegexOptions.ExplicitCapture)
Dim matches As MatchCollection = regexHour.Matches(value)

If matches.Count = 1 Then
  With matches(0)
    ' (!) The first group is always the expression itself. '
    If .Groups.Count = 3 Then ' hours : minutes '
      strHours = .Groups("hours").Value
      If String.IsNullOrEmpty(strHours) Then strHours = "0"
      strMinutes = .Groups("minutes").Value
    Else ' there are 1, 3 or > 3 groups '
      success = False
    End If
  End With
Else
  success = False
End If

Thanks everybody contributing to this answer!