Need a Python field calculation that works like the DatePart( ) VB Function

Question

I have a field called Abandoned Year (short integer data type) that I am trying to populate with a four digit year from a column called Decommission Date (Date data type). I have done this in the past using the DatePart( ) VB function but how do I accomplish this same task in a Python field calculation?

Here is the code written in VB:

AbandonedYear = DatePart ("YYYY", [DecommissionDate])

Thanks

Answer 1

Try this:

AbandonedYear = datetime.datetime.strptime( !DecommissionDate! , '%m/%d/%Y %I:%M:%S %p').year

You may need to change the format, if so a reference for those format strings is found here: Python Documentation

Answer 2

I built a field calculator expression using Python that behaves like that nice DatePart function in VB. I just [Load...] my *.cal file whenever I need it. Yes, I know there's much more Pythonic ways of doing this, but I just like the familiar simplicity and not having to remember that ArcGIS treats datetimes as text strings during field calculations.

def datePart( outpart, ArcGISDateField ):

    # var outpart must be one: "YYYY" | "M" | "D" | "hh" | "mm" | "ss"

    # var indatetime must take the form of either "M/D/YYYY" or "M/D/YYYY hh:mm:ss AP"
    # My Windows Date and Time settings ensure this form.

    inparts = ArcGISDateField.split(" ")
    if( len(inparts) == 1):
        inparts.extend(["00:00:00","AM"])
    inparts[0] = inparts[0].split("/")
    inparts[1] = inparts[1].split(":")   

    # build a dictionary to store the date and time parts
    outparts = {}
    outparts["M"] = int(inparts[0][0])
    outparts["D"] = int(inparts[0][1])
    outparts["YYYY"] = int(inparts[0][2])
    outparts["mm"] = int(inparts[1][1])
    outparts["ss"] = int(inparts[1][2])
    if( inparts[2] == "AM" ):
        outparts["hh"] = int(inparts[1][0])
    else:
        outparts["hh"] = int(inparts[1][0]) + 12

    # Grab and return the value of the date part I want
    return outparts[outpart]

Outfield = datePart("hh",!timestamp!)