converting a month name to month ordinal

   How can I convert a month's name into a ordinal number? The months are three lettters and need to be converted to number value:
jan = 01
feb =02
mar =03

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its only 12 cases....i would just use a select case..

private sub ReturnMtnhOrdinal(byval MonthName as string) as integer
  dim MonthOrdinal as integer
  select case MonthName.ToLowerString
    case "jan"
      monthOrdinal = 1
    case "feb"
      monthOrdinal = 2
    case "mar"
      monthOrdinal = 3
    case "apr"
      monthOrdinal = 4
    case "may"
      monthOrdinal = 5
    case "jun"
      monthOrdinal = 6
    case "jul"
      monthOrdinal = 7
    case "aug"
      monthOrdinal = 8
    case "sep"
      monthOrdinal = 9
    case "oct"
      monthOrdinal = 10
    case "nov"
      monthOrdinal = 11
    case "dec"
      monthOrdinal = 12
    case else
      monthordinal = 0
  End Select

  Return MonthOrdinal

end sub
Where are the three-letter month names coming from?  Are they being read from a file?  Entered into textboxes on a form?

You could define the three-letter names as class variables and set them equal to the numbers

i.e.  Dim jan as integer = 01
       Dim feb as integer = 02

If you have previously validated the month:

nMonth = Int("janfebmaraprmayjunjulaugsepoctnovdec".IndexOf(sMonthName.ToLower) / 3) + 1

If not:

nMonth = Int("jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec|".IndexOf(sMonthName.ToLower & "|") / 4) + 1

In both cases an invalid month will return 0

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Mike TomlinsonHigh School Computer Science, Computer Applications, Digital Design, and Mathematics TeacherCommented:

    Private Function GetMonthOrdinal(ByVal month As String) As Integer
        Return Array.IndexOf("jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec".Split("|".ToCharArray), month.ToLower) + 1
    End Function

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Bob LearnedCommented:
   Dim month As Date = "01 Feb"
    Dim number As Integer = month.ToString("MM")

Sample with Enums.....

   Enum Months
        Jan = 1
        Feb = 2
        Mar = 3
        Apr = 4
        May = 5
        Jun = 6
        Jul = 7
        Aug = 8
        Sep = 9
        Oct = 10
        Nov = 11
        Dec = 12
    End Enum

        Dim s As String
        For Each s In [Enum].GetNames(NumMonths)
            Console.WriteLine("{0,-11} = {1}", s, [Enum].Format(NumMonths, [Enum].Parse(NumMonths, s), "d"))
        Next s
        'OUTPUT DATA
        'Jan = 1
        'Feb = 2
        'Mar = 3
        'Apr = 4
        'May = 5
        'Jun = 6
        'Jul = 7
        'Aug = 8
        'Sep = 9
        'Oct = 10
        'Nov = 11
        'Dec = 12
Bob LearnedCommented:
I guess this all goes to prove that there are so many ways to skin a cat :)

Sorry forgot this

        Dim NumMonths As Type = GetType(Months)
Hey, go for it Bob
Mike TomlinsonHigh School Computer Science, Computer Applications, Digital Design, and Mathematics TeacherCommented:
If you really needed that leading zero then...

    Private Function GetMonthOrdinal(ByVal month As String) As String
        Return (Array.IndexOf("jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec".Split("|".ToCharArray), month.ToLower) + 1).ToString("00")
    End Function
Can anyone play?

    Private Function MonthToOrdinal(ByVal m As String) As Integer
        Dim s As String = "01/" & m & "/2005"
            Dim d As Date = s
            Return d.Month
        Catch ex As Exception
            MsgBox("Invalid Date")
            Return -1
        End Try
    End Function

Catches location differences and full month names as well.

Bob LearnedCommented:
Yes, Roger, I think that anyone can play ;)

I think we done shot some serious holes in this one :)

Mike TomlinsonHigh School Computer Science, Computer Applications, Digital Design, and Mathematics TeacherCommented:
I like yours the best Roger!

I like seeing all the creative answers though and it's nice to see so many responses when most of these experts know they won't get the points for such a simple question...

Personally, I wanted to see how much code I could cram into a one liner function.   ;)
Bob LearnedCommented:
ROFL :))

I like Roger's best, too :)

Mike, you win the longest single line prize :)

I agree I like Roger's answer. :)
Bob LearnedCommented:
In fact, Roger's code is going into the code vault :)

Bob LearnedCommented:
Simplification complete:

    Public Shared Function MonthNameToOrdinal(ByVal name As String) As Integer

      If IsDate("01 " & name) Then
        Return DateTime.Parse("01 " & name).Month
        Return -1
      End If

    End Function 'MonthNameToOrdinal'

Notice the missing Exception handling, the missing year, and the missing date separator.

Leave it to Bob to come up with a short cut! lolol :)
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