[R] for loop and if problem

[Sake]

Sake wrote:
> 
> Hi,
> 
> I'm heaving difficulties with a dataset containing gene names and
> positions of those genes.
> Not such a big problem, but each gene has multiple exons so it's hard to
> say where de gene starts and where it ends. I want the starting and ending
> position of each gene in my dataset.
> Attached is the dataset:
> http://www.nabble.com/file/p21312449/genlistchrompos.csv
> genlistchrompos.csv 
> Column 'B' is the gene name, 'G' is the starting position and 'H' is the
> stop position.
> You can load the dataset by using: data<-read.csv("genlistchrompos.csv",
> sep=";")
> I hope someone can help me, it's giving me headaches for a week now:-((.
> 
> Thanks! 
> 
> 

Thanks for the tips, i'm going to test them today!
The B,G,H columns I mentioned are the columns you see when you open the file
in Excel, I should have said that. Sorry for the confusion about that:-)
I thought I had to use the 'if' statement because I only want to search for
the Min and Max if the Gene name is the same as the one directly under it.
And the 'for loop' I wanted to use to apply the 'if' statement to the entire
row of gene names.

Edit:
I have tested:
aggregate(data[, c("Exon_Start.Chr.")], by = list(data$Gene), min) 
aggregate(data[, c("Exon_Stop.Chr.")], by = list(data$Gene), max)

And it worked like a charm!
thanx!
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