[R] Append data to vector form a column of a dataframe

[Wolfgang Wu]

In addition to Ivan, test$a is not a data.frame anymore but a numerical vector.

> class(test$a)
[1] "numeric"
> test$a
[1] 1 2 3

So adding a row to your data.frame would be 

> rbind(test, 2)
  a
1 1
2 2
3 3
4 2


 
Wolfgang Wu


----- Ursprüngliche Message -----
Von: Ivan Calandra <ivan.calandra at uni-hamburg.de>
An: r-help at r-project.org
Cc: 
Gesendet: 11:19 Mittwoch, 12.Oktober 2011 
Betreff: Re: [R] Append data to vector form a column of a dataframe

Hi Dom,

This is because "3" is recycled. It is necessary because the number of 
columns have to be the same for every row.

Try this instead:
c(test$a, 2)  ## you wrote "3" but meant "2" I guess

HTH,
Ivan

Le 10/12/2011 10:47, behave a écrit :
> Dear R-community,
>
> When doing this:
>
>> test<-data.frame(a=c(1,2,3))
>> rbind(test$a, 3)
> I expect something like:
>
>> 1
>> 2
>> 3
>> 2
> but get:
>>      [,1] [,2] [,3]
>> [1,]    1    2    3
>> [2,]    2    2    2
>
> the same for:
>
> rbind(test[["a"]], 2)
> or
> rbind(as.vector(test[["a"]]), 2)
> or
> rbind(t(as.vector(test[["a"]])), 2)
>
> Why is that and how do I extract the "values" from a dataframe to get the
> desired result?
>
> Thank you
> Dom
>
>
>
>
>
>
>
>
> --
> View this message in context: http://r.789695.n4.nabble.com/Append-data-to-vector-form-a-column-of-a-dataframe-tp3897205p3897205.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

-- 
Ivan CALANDRA
PhD Student
University of Hamburg
Biozentrum Grindel und Zoologisches Museum
Dept. Mammalogy
Martin-Luther-King-Platz 3
D-20146 Hamburg, GERMANY
+49(0)40 42838 6231
ivan.calandra at uni-hamburg.de

**********
http://www.for771.uni-bonn.de
http://webapp5.rrz.uni-hamburg.de/mammals/eng/1525_8_1.php

______________________________________________
R-help at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.