# [R] Identyfing rows with specific conditions

Bert Gunter bgunter.4567 at gmail.com
Mon May 22 05:11:11 CEST 2017

Clarification:

Does each customer have the same number of meals or do they differ
from customer to customer? If the latter, how are missing meals
notated? Do they always occur at the (right) end or can they occur
anywhere in the row?

Presumably each customer ID can have many different meal code
combinations, right ?(since they can have 30 different meals with
potentially 30 choose 2 = 435 combinations apiece)

Please make sure you reply to the list, not just to me, as I may not
pursue this further but am just trying to clarify for anyone else who
may wish to help.

Cheers,
Bert

Bert Gunter

"The trouble with having an open mind is that people keep coming along
and sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )

On Sun, May 21, 2017 at 5:10 PM, Allaisone 1 <allaisone1 at hotmail.com> wrote:
>
> Hi All..,
>
> I have 2 tables. The first one contains 2 columns with the headers say "meal A code" & "meal B code " in a table called "Meals" with 2000 rows each of which with a different combination of meals(unique combination per row).
>
>
>>Meals
>
>     meal A code      meal B code
>
> 1          34                   66
>
> 2           89                  39
>
> 3           25                   77
>
> The second table(customers) shows customers ids in the first column with Meals codes(M) next to each customer. There are about 300,000 customers (300,000 rows).
>
>> Customers
>      1         2     3       4    ..30
>      id       M1  M2   M3
> 1   15      77    34    25
> 2   11      25    34     39
> 3    85     89     25    77
> .
> .
> 300,000
>
> I would like to identify all customers ids who have had each meal combination in the first table so the final output would be the first table with ids attached next to each meal combination in each row like this:
>
>>IdsMeals
>
>
>   MAcode  MBcode  ids
>
> 1     34        39            11
>
> 2     25       34              15   11
>
> 3      25     77                15   85
>
> Would you please suggest any solutions to this problem?
>
> Regards
>
>         [[alternative HTML version deleted]]
>
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