[R] Changing names of a string variable

[Jahan]

Hello,
Here is the data set I am working with:
dat=read.csv('http://dl.dropbox.com/u/1852742/relexpressions.csv')
names(dat)

#Under the 'target' column, I want to change all of the values into
all capital letters (e.g. fgf2 becomes FGF2).  I have taken a loop
approach but I think my Python background is confusing me.  Here is
what I attempted:

for(line in dat[,1]){if(line=='fgf2'){line<-'FGF2'}}
#I made sure that it was looping through each line by entering:
for(line in dat[,1]){if(line=='fgf2'){print(line)}} #Which did exactly
what I thought it would.

#This doesn't change anything, though.  Also, after reading the
documentation I am still confused how to add multiple "if"
statements.  I would need that because I need to change the names of
fgf2, fgf7, and fgf10.

#I am sure there is a built-in function to do what I need, but I
haven't found it yet so I tried this loop method.  Any help is greatly
appreciated!

Jahan