Level 2 Sprint 3 SYS01 line items

LStinsa

I am struggling with the beginning inventory formula.  I feel confident with the later part of the formula but I don't see how I am going to rule out that it is the first week of the year.  Should I add a line item to my module?

 

 

einas.ibrahim

Hello @LStinsa 

You can programmatically determine the first period in your model (and the last period too). While there isn't a specific function to directly return this value, you can use a time series function
Some of the time series functions include a fill value parameter, which is basically a value the model builder specifies and expects it to be returned in case we reach the boundaries of the model timeline i.e. a period outside of the model's time range. 
For example, you specify the fill value to -1 or 999 or any other value that you wouldn't get as a result of the function and compare.
IF time series function(x,y, -1) = 999 THEN you know you reached the "edges" of your model timeline.

I left the exact function to use vague because:
1. There is more than 1 that could be used, based on the situation.
2. I'd like you to look at the time series functions in the link above and try to figure it out.

However, if you still need help, please let me know and I'll walk you through it.