2 Replies Latest reply on Sep 26, 2012 6:13 PM by LaRetta_1

# How to convert the Week No. back to a date?

### Title

How to convert the Week No. back to a date?

### Post

How to convert the Week No. back to a date?

For example, I have the week no.=1 of the year 2012

Any one know ehat formula or script can convertit back to a date like 01/01/2012?

Thanks

maggie

• ###### 1. Re: How to convert the Week No. back to a date?

OS - Win or Mac - version?  FMP version?
Field Name? Field Type (calculation?)?

Normally, weekofyear is used with a calculation field to get the week number. This means that there had to have been a date field.

If the date field exists, you have the information in the database.

• ###### 2. Re: How to convert the Week No. back to a date?

Hi Maggie!!  Assuming the following:

You have a number field which holds the WeekOfYear number (let's call it numWks).  And you have a date field which can specify the year (otherwise change the bold portion in the calc to use a year number):

Let ( [
start = Date ( 1 ; 1 ; Year ( date ) ) ;
firstSun = start - DayOfWeek ( start )
] ;
firstSun + 7 * numWks
)

... will give you the last day of that week (Saturday), notice the -6 to back the date to the Sunday date.

Let ( [
start = Date ( 1 ; 1 ; globalYearField  ) ;
firstSun = start - DayOfWeek ( start )
] ;
firstSun + 7 * numWks - 6
)

... will give you the first day of that week (Sunday).  Use either the date to get the year or a year field (I provided both examples).

I had the -6 reversed and I've changed it.