creating and then executing command strings

Hi:

I very recently started experimenting with R and am occasionally
running into very basic problems that I can't seem to solve. If there
is an R-newbies forum that is more appropriate for these kinds of
questions, please direct me to it.

I'd like to automatically add vectors to a dataframe. I am able to
build command strings that would do what I want, but R is not
executing them.

A simplified example:

# Add three vectors called avg_col1, avg_col2, avg_col3 to dataframe df
for(colname in c("col1", "col2", "col3")){
	print(paste("df$avg_",colname, " <- 0;", sep='')) # Just using this
to make sure the command is correct
	paste("avg_",colname, " <- 0;", sep='') # Does nothing
}

Output:

[1] "df$avg_col1 <- 0;"
[1] "df$avg_col2 <- 0;"
[1] "df$avg_col3 <- 0;"

Thanks for your help!

Best - P