dataframe: string operations on columns
On 2011-01-18 08:14, Ivan Calandra wrote:
Hi,
I guess it's not the nicest way to do it, but it should work for you:
#create some sample data
df<- data.frame(a=c("A B", "C D", "A C", "A D", "B D"),
stringsAsFactors=FALSE)
#split the column by space
df_split<- strsplit(df$a, split=" ")
#place the first element into column a1 and the second into a2
for (i in 1:length(df_split[[1]])){
df[i+1]<- unlist(lapply(df_split, FUN=function(x) x[i]))
names(df)[i+1]<- paste("a",i,sep="")
}
I hope people will give you more compact solutions.
HTH,
Ivan
You can replace the loop with
df <- transform(df, a1 = sapply(df_split, "[[", 1),
a2 = sapply(df_split, "[[", 2))
Peter Ehlers
Le 1/18/2011 16:30, boris pezzatti a ?crit :
Dear all, how can I perform a string operation like strsplit(x," ") on a column of a dataframe, and put the first or the second item of the split into a new dataframe column? (so that on each row it is consistent) Thanks Boris