[R] ' quote problem in reading lots of files at once

Srinivas Iyyer srini_iyyer_bio at yahoo.com
Mon Sep 11 18:35:38 CEST 2006


Dear group, 
 i have 114 files (all have 5 columns) and variable
number of rows. 

I want to read all the files and select the first
column and 4th column and fill the values into a big
matrix. I have a pre-made matrix that would have all
rownames (1st column) and coloumn names (4th column
from file to be read). 

mymat <- matrix(data = 1, nrow = length(gomfs), ncol =
length(x))
rownames(tarmat)<-gomfs
colnames(tarmat)<-x

# here gomfs is a large set of rownames from the files
to be read. 
# x (114 files)

for(i in x){
        xa <- read.table(i,sep='\t')
        a2 <- as.character(xa[,1])
        a3 <- xa[,4]
        nd <- data.frame(a2,a3)
        tarmat[a2,i] = a3
}



What is the problem then:

The problem is a2 has ' (single quotes).  So when a2
does not have singles quote, everything works fine.
But when a2 has ' - then starting from there to the
EOF all values are cluttered. 

Example:

> a2[49]
[1] "mRNA guanylyltransferase activity"


> a2[50]
[1] "polynucleotide 5-phosphatase
activity\t1\t1\t0.0160650535501781\t0.0160650535501781\t0.0664390950962566\nribulose-phosphate
3-epimerase
activity\t1\t1\t0.0160650535501781\t0.0160650535501781\t0.0664390950962566\n


How can I escape the ' quote character when I read
each file. So that I do not have the problem of
clutter and my matrix is read well.


Thank you.



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