How to input for the first Item while using the Previous Function

neg177
neg177
in Modeling

Hi,

 

I would like to know how I can input the first number that I need my Previous Function to read from. I know I need to add to the formula but not sure what to do. Please advice. Images attached. 

 

Thank you 

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Answers

  • ChrisAHeathcote
    ChrisAHeathcote

    @neg177 

    Are you looking for the ability to specify which previous value you would like to pull into a cell?

    If so, use the OFFSET function and specify the number of time periods in the past you wish to pull across. 

  • rob_marshall
    rob_marshall

    @neg177 

     

    What is that value supposed to be, a zero since I believe it is the first period of your Time Calendar?  If so, use Lag() as the last parameter can be used as the default.

     

    Rob

  • KirillKuznetsov
    KirillKuznetsov

    Hi @neg177 

    If the previous hints won't help please try this.

    In my understanding, you want some initial numbers in the very first period of your timescale. 

    For that, I would use a separate module with no time scale but the rest dimensions are the same. Then edit your formula to have an IF THEN function where you would refer to this new module if a period is the first one.  

    The formula should be like this:

    IF START() = <a new line item with initial period> THEN <new module> ELSE PREVIOUS(Ending RTR Balance)

     

    Kirill

  • KirillKuznetsov
    KirillKuznetsov

    You actually even can combine with the previous answers.

    Both OFFSET and LAG function have this last argument "Substitute value". 

    OFFSET(Value to offset, Number of periods, Substitute value) 
    LAG(Value to offset, Offset amount, Substitute value [, Non-positive behavior])

     You can add <new module> as your substituted value.

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