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

mdf <- data.frame(1:3)
names(mdf) <- "147"

i <- 147

mdf[ as.character(i) ]

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) }

}




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