Hi,
You can either parse and eval the string you are making, as in:
eval( parse( text = paste("avg_",colname, " <- 0;", sep='') ) )
Or you can do something like this:
df[[ paste( "avg_", colname, sep = "" ) ]] <- 0
Romain
Philipp Schmidt wrote:
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
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--
Romain Francois
Independent R Consultant
+33(0) 6 28 91 30 30
http://romainfrancois.blog.free.fr
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and provide commented, minimal, self-contained, reproducible code.
