[R] Set attributes for object known by name

[Peter Langfelder]

oops, I think the right code would be

x = get(varname)
attr(x, "foo") = "bar"
assign(varname, x)

On Wed, Oct 10, 2018 at 9:30 PM Peter Langfelder <peter.langfelder using gmail.com>
wrote:

> I would try something like
>
> x = get(myvarname)
> attr(x, "foo") = "bar"
> assign(varname, x)
>
> HTH,
>
> Peter
>
> On Wed, Oct 10, 2018 at 9:15 PM Marc Girondot via R-help <
> r-help using r-project.org> wrote:
>
>> Hello everybody,
>>
>> Has someone the solution to set attribute when variable is known by name ?
>>
>> Thanks a lot
>>
>> Marc
>>
>> Let see this exemple:
>>
>> # The variable name is stored as characters.
>>
>> varname <- "myvarname"
>> assign(x = varname, data.frame(A=1:5, B=2:6))
>> attributes(myvarname)
>>
>> $names
>> [1] "A" "B"
>> $class
>> [1] "data.frame"
>> $row.names
>> [1] 1 2 3 4 5
>>
>> # perfect
>>
>> attributes(get(varname))
>>
>> # It works also
>>
>> $names
>> [1] "A" "B"
>> $class
>> [1] "data.frame"
>>
>> $row.names
>> [1] 1 2 3 4 5
>>
>> attributes(myvarname)$NewAtt <- "MyAtt"
>>
>> # It works
>>
>> attributes(get(varname))$NewAtt2 <- "MyAtt2"
>> Error in attributes(get(varname))$NewAtt2 <- "MyAtt2" :
>>    impossible de trouver la fonction "get<-"
>>
>> # Error...
>>
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>

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