[R] Adding markers and text for some data points after drawing a plot

[David Winsemius]

On Feb 26, 2013, at 1:04 PM, Debs Majumdar wrote:

> Hi All,
> 
> I have a data set of around 17,000 gene names and their lengths. E.g.
> 
>           gene      kblength    
>  A3GALT2       14.333    
> AADACL3       12.609    
> AADACL4       22.532    
>      ABCA4     128.312    
>     ABCB10      42.114    
>       ABCD3    100.287    
> ............
> .........
> 
> and I was able to draw a reverse cumulative frequency plot using the following code:
> d <- read.table("gene_length_data.txt", header=T)
> attach(d)

Using 'attach' is a bad idea. In particular we have trouble keeping straight what is a column name or a first class object in your workspace.

> kblength.ecdf <-ecdf(kblength)
> r <-range(kblength)
> curve(1-kblength.ecdf(x), from=r[1], to=r[2], col="red", xlim=r)
> detach(d)

> Here's the link to the output: http://www.tiikoni.com/tis/view/?id=5c41810
> 
> I want to put markers

Use points()

> and the corresponding gene names in the graph for a small list of 6 genes. i.e. say a hollow circle on the curve followed by the corresponding gene name.


text(x= d[ which( d[['gene']]=="AADACL4"), 2], 
     y= kblength.ecdf( d[ which( dat[['gene']]=="AADACL4"), 2]), 
    "AADACL4")
> 
> I am fighting with this but wasn't able to get a solution.

> 
> Any help is appreciated.
> 
> Thanks,
>  Debs
> 
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-- 
David Winsemius
Alameda, CA, USA