R package reshape function melt error: id variables not found in data when working with a lot of factors

I am working with a rarefaction output from mothur, which basically gives me a dataset containing the number of sequences sampled and the number of unique sequences in several samples. I would like to use ggplot2 to visualize this data and therefore need to use melt to go from a wide to a long format.

The problem is that I find no way to make this work due to an error of melt. Which basically states

Error: id variables not found in data: 1,3,6, (... and so on)

Because of the size of the original dataset it would be impractcal to share it here nonetheless one should be able to recreate the same problem using the following code:


Which gives exactly the same error:

Error: id variables not found in data: 0,3,6,9, (...)

I fail to see what I am doing wrong. I am using R 2.15.1 on ubuntu server 12.04. Both the function reshape::melt and reshape2::melt result in the same error.


You should use:

melt(d, id.vars="a")
      a variable       value
1     0        b 0.019199459
2     3        b 0.693699677
3     6        b 0.937592641
4     9        b 0.299259963
5    12        b 0.485403439

From the help of ?melt.data.frame:

data data frame to melt

id.vars vector of id variables. Can be integer (variable position) or string (variable name)If blank, will use all non-measured variables

Thus your id.vars argument should be a character vector of names, e.g. "a" or a numeric vector, e.g. 1. The length of this vector should equal the number of columns you want as your id.

Instead, you used a factor that contained far more elements than you have columns in your data.

Need Your Help

different jvms with different encodings

java encoding

Suppose I have 2 jvms running - 1 is a client and the other is a server. Suppose the client and server are using different encodings. If I write a program on the client which sends Strings across the

PasteBin API bug? not allowing simple post

php string api post pastebin

I'm trying to make a php api request to simply make a simple paste to pastebin and i found an example at http://pastebin.com/api and it's pretty strait forward so i didnt think there would be any

About UNIX Resources Network

Original, collect and organize Developers related documents, information and materials, contains jQuery, Html, CSS, MySQL, .NET, ASP.NET, SQL, objective-c, iPhone, Ruby on Rails, C, SQL Server, Ruby, Arrays, Regex, ASP.NET MVC, WPF, XML, Ajax, DataBase, and so on.