Calculating the number of days from given dates givesa null value!

[mostwanted]

I am lost for words & a-little infuriated at this point, a formula that has been working & is working in other applications is not working today when applied to another app!!

I am simply trying to get the number of days from the given dates but the formula gives a NONE value! But i have applied it in the same as in other apps, no changes at all!

CODE

from datetime import datetime

db.define_table('invoice',
                Field('customer', 'reference Client_Details',writable=False, label=SPAN('Customer', _style="font-weight: bold;")),
                Field('client_order', label=SPAN("Item", _style="font-weight: bold;"), requires=IS_NOT_EMPTY()),
                Field('loaning_date', 'date', label=SPAN('Date Loaned', _style="font-weight: bold;"), requires=IS_NOT_EMPTY()),
                Field('returning_date', 'date', label=SPAN('Date Returned', _style="font-weight: bold;"), requires=IS_NOT_EMPTY()),
                Field('daysLoaned', 'integer', compute=lambda r: (datetime.strptime(r['returning_date'], '%Y-%m-%d') - datetime.strptime(r['loaning_date'], '%Y-%m-%d')).days))

The highlited field saves a None value which is not what i am trying get!!




Please help!




Mostwanted

[Dave S]

Since you are working with date fields, just do the time timedelta directly.

I don't know where the None comes from, but why bother with strptime?

/dps