[R] how to get all strings in a data frame that start with a particular string

[Ana Marija]

Hello,

Hello,

I have a data frame (tot) with about 2000 columns. How can I extract
from it all strings that start with E14?

I tried this:
e14 <- sapply(tot, function(x) grepl("^E14", x))

but this returns me just TRUE and FALSE vector, how do I get actual
strings that start with E14?

Thanks
Ana