> Hi J'ers,
>
> I'm trying to write a verb that will
> match the items in Source with Target
> and return the index of items in Target
> such that they are in the same order as
> Source with nulls (or the J way of handling nulls)
> if no match is found.
>
> This is what i have (and it's wrong):
>
> Source =. 'a';'bcd';'e';'g'
> Target =. 'e';'a';'bcd';'f'
> getIndex =: e.
> shouldReturn =. 1 2 0 null
> assert (Source getIndex Target)=shouldReturn
>
Hi Joe,
i. may be what you are looking for:
Source =. 'a';'bcd';'e';'g'
Target =. 'e';'a';'bcd';'f'
Target i. Source
1 2 0 4
null is here represented with 4, which in general equals #Target, so
Target =. 'e';'a';'bcd'
Target i. Source
1 2 0 3
> In the forums I've found solution candidates,but
> haven't been able to apply them and am a bit lost with:
> I.@:E. and ;:
>
> The concept of expressing null or missing data in J I haven't
> found much info on. Where can i find more information on nulls.
>
> Much Thanks -Joe
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