[R] Adding columns to a tibble based on a value in a different tibble

[@vi@e@gross m@iii@g oii gm@ii@com]

Yes, Bert. At first glance I thought it was one of the merge/joins and then wondered at the wording that made it sound like the ids may not be one per column.

IFF the need is the simpler case, it is a straightforward enough and common need. An example might make it clear enough so actual code can be shared as compared to talking about a first and second tibble.

Here is one reference to consider:

https://r4ds.hadley.nz/joins.html#:~:text=dplyr%20provides%20six%20join%20functions,is%20primarily%20determined%20by%20x%20.


A left_join may be what works, and of course more basic R includes the merge() function:

https://www.rdocumentation.org/packages/base/versions/3.6.2/topics/merge

If the column were to contain multiple ID, that changes things and a more complex approach could be needed.

-----Original Message-----
From: R-help <r-help-bounces using r-project.org> On Behalf Of Bert Gunter
Sent: Saturday, November 4, 2023 10:35 AM
To: Alessandro Puglisi <alessandro.puglisi using gmail.com>
Cc: r-help using r-project.org
Subject: Re: [R] Adding columns to a tibble based on a value in a different tibble

I think a simple reproducible example ("reprex") may be necessary for you
to get a useful reply. Questions with vague specifications such as yours
often result in going round and round with attempts to clarify what you
mean without a satisfactory answer. Clarification at the outset with a
reprex may save you and others a lot of frustration.

Cheers,
Bert

On Sat, Nov 4, 2023 at 1:41 AM Alessandro Puglisi <
alessandro.puglisi using gmail.com> wrote:

> Hi everyone,
>
> I have a tibble with various ids and associated information.
>
> I need to add a new column to this tibble that retrieves a specific 'y'
> value from a different tibble that has some of the mentioned ids in the
> first column and a 'y' value in the second one. If the id, and so the 'y'
> value is found, it will be included; otherwise, 'NA' will be used.
>
> Could you please help me?
>
> Thanks,
> Alessandro
>
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>
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