[R] Problem with Median

[Suhaila Haji Mohd Hussin]

I might be silly but if I was going to type in dput() then how should I send the data over here? 
Instead, I've just uploaded the image online, you can access it via the link below.
http://i1165.photobucket.com/albums/q585/halfpirate/data.jpg 

> Date: Mon, 7 May 2012 14:55:24 -0400
> Subject: Re: [R] Problem with Median
> From: sarah.goslee at gmail.com
> To: bell_beauty12 at hotmail.com
> CC: r-help at r-project.org
> 
> Please use dput() to give us your data (eg dput(data) ) rather than
> simply pasting it in.
> 
> Sarah
> 
> On Mon, May 7, 2012 at 2:52 PM, Suhaila Haji Mohd Hussin
> <bell_beauty12 at hotmail.com> wrote:
> >
> > Hello.
> > I'm trying to compute median for a filtered column based on other column but there was something wrong. I'll show how I did step by step.
> > Here's the data:
> >     a     b     c      class
> >
> > 1   12   0      90     A-B2   3     97    11     A-B3   78   NA    123   A-C4   NA   NA    12    A-C5   8     33     2     A-B6   12   NA     0     A-D
> > On the command I typed:
> > 1) data = read.csv("data.csv")
> >
> > 2) a.AC <- subset(data, class == "A-C", select = a)
> > 3) median(a.AC)Error in median.default(a.AC) : need numeric data
> > 4) is.numeric(a.AC)FALSE
> > 5) as.numeric(a.AC)Error: (list) object cannot be coerced to type 'double'
> > How can I fix this? Please help.
> > Cheers,Suhaila
> 
> 
> -- 
> Sarah Goslee
> http://www.functionaldiversity.org