[R] Help with "For" instruction

Sarah Goslee sarah.goslee at gmail.com
Tue Jan 4 18:58:39 CET 2011


2011/1/4 André Dias <diasandre at gmail.com>:
> hi
>
> how do I exactly use the get(). I am reading the help for get() but the way
> I am using it causes an error/
>

So how are you using it? It's so much easier to explain what you're doing
wrong if I know what you're doing.

Without a reproducible example I can't show you exactly, but
something like:

 for (i in 1:length(database))
assign(paste("distancematrix",i,sep=""), dist(get(paste("database", i,
sep=""))))

get() is the counterpart of assign(), though there are better (more R-ish)
ways of doing what you want.

Sarah


> thanks
> ADias
>
> 2011/1/4 Sarah Goslee <sarah.goslee at gmail.com>
>>
>> With get().
>>
>> On Tue, Jan 4, 2011 at 11:58 AM, ADias <diasandre at gmail.com> wrote:
>> >
>> > Hi,
>> >
>> > Still with the above problem:
>> >
>> > But for instance, i have a data base with 30 variables and I created an
>> > object each with one varibale missing:
>> >
>> > DataBase - has 30 variables
>> > DataBase1 has 29 variables with the 1st variable gone
>> > DataBase2 has 29 variables with the 2nd variable gone
>> >
>> > for(i in 1:length(database))
>> > assign(paste("database",i,sep=""),database[-i])
>> >
>> >
>> > Now, I wish to create the 30 distance matrix:
>> >
>> > for (i in 1:length(database))
>> > assign(paste("distancematrix",i,sep=""),
>> > dist(database[i]))
>> >
>> > But doing like this - database[i] - I am just refering to the 1st value
>> > on
>> > the object database and not to the entire database i.
>> >
>> > How do I do this?
>> >
>> > thanks
>> > Regards,
>> > A.Dias
>> > --
>> --

-- 
Sarah Goslee
http://www.functionaldiversity.org



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