R-help: grep in for loop using index - doesn't work

Thanks Phil.  

That worked. 

The apply(..) commands gives me a single 1/0 output for each column which
has the query item or not. 

But I am looking to find the index i from the loop to extract that
particular value for plotting

I'll try to improve the data.frame part; I was not able to access the rows
with data (just started R), so I created individual frames for data

Cheers
Mohan


-----Original Message-----
From: Phil Spector [mailto:spector at stat.berkeley.edu] 
Sent: Wednesday, March 11, 2009 10:46 PM
To: Mohan Singh
Subject: Re: [R] R-help: grep in for loop using index - doesn't work

Mohan -
    "i" is the literal character i.  i is the variable called
i.  In this case, you want the variable, i.e. i:

   p1 <- grep("QueryItem",c1data[i,],value=FALSE,fixed=FALSE)

I might also mention that creating a separate data frame for each
column of your data is not really a good idea.  I believe that you're
looking for a solution like

     apply(data,2,grep,"Query Item")

but it's hard to tell.  You might want to run that command 
and see if what you want is in the output.

                                        - Phil Spector
 					 Statistical Computing Facility
 					 Department of Statistics
 					 UC Berkeley
 					 spector at stat.berkeley.edu

Hi everyone



 I am trying to use grep in a for loop to compare a string value. It works
if I use the actual index value but when I use the for loop index, it
doesn't work. Any suggestions plz.



Here is the code:



data <- read.table(file="Sigmoid.csv", head=FALSE, sep=",");



c1 <- data$V1

c2 <- data$V2

c3 <- data$V3



c1data <- data.frame(c1);

c2data <- data.frame(c2);

c3data <- data.frame(c3);



#this works

p <- grep("QueryItem",c1data["147",],value=FALSE,fixed=FALSE)

print(p) # print 1



#doesn't work

i<-147

p1 <- grep("QueryItem",c1data["i",],value=FALSE,fixed=FALSE)

print(p1) # prints 0



for(i in 137:270) {

 print(i)

 p <- grep("QueryItem",c1data["i",],value=FALSE,fixed=FALSE)

 p2 <- p

 print(p2)

 if(length(p)>0) { print(p) }

}




	[[alternative HTML version deleted]]

______________________________________________
R-help at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide

http://www.R-project.org/posting-guide.html

and provide commented, minimal, self-contained, reproducible code.