Find string in data.frame

Question

How do I search for a string in a data.frame? As a minimal example, how do I find the locations (columns and rows) of \'horse\' in this data.frame?

Answer 1

Another way around:

l <- sapply(colnames(df), function(x) grep("horse", df[,x]))

$animal
[1] 2 3

$level
[1] 5

$length
[1] 4

If you want the output to be matrix:

sapply(l,'[',1:max(lengths(l)))

     animal level length
[1,]      2     5      4
[2,]      3    NA     NA