Changing date format in field name from d2000_5000 to Dddmmyyyy? [closed]

Question

I am trying to change the name of a field by using Python code where the current name is in the format (e.g.) d2000_5000, and 5000 is the decimal year (0,5 y) added to 2000. So i think that this can be done with the Alter Field tool, by extracting characters, then doing 365*5000/10000 to obtain days, and then adding these days to the initial date of 2000: 2000-01-01 + days (within a date sum that takes into account years with 29 days in Feb).

Somebody can help me proposing a code snip to do it?

Answer 1

Use the datetime module:

def fixdate(oldfieldname):
    from datetime import datetime, timedelta
    import re

    #Extract numbers using re module and convert to decimal year
    newfieldname = [int(s) for s in re.findall(r'\d+', oldfieldname)]
    newfieldname[1] = newfieldname[1]/1000
    newfieldname = float(str(newfieldname[0])+"."+str(int(newfieldname[1])))

    #Use datetime module to go from decimal year to datetime and ddmmyyyy
    year = int(newfieldname)
    rem = newfieldname - year
    base = datetime(year, 1, 1)
    result = base + timedelta(seconds=(base.replace(year=base.year + 1) - base).total_seconds() * rem)
    return 'D'+result.strftime('%d%m%Y')

For example:

fixdate('d2000_5000')
'D02072000'

And to alter field name:

arcpy.AlterField_management(r'C:\database\feature_class123', 'd2000_5000', fixdate(
    'd2000_5000'))