Remove all rows where length of string is more than n

Question

I have a dataframe m and I want to remove all the rows where the f_name column has an entry greater than 3. I assume I can use something similar to

m <- m[-grep("nchar(m$f_name)>3", m$f_name]

Answer 1

For those looking for a tidyverse approach, you can use dplyr::filter:

m %>% dplyr::filter(nchar(f_name) > 3)

Answer 2

To reword your question slightly, you want to retain rows where entries in f_name have length of 3 or less. So how about:

subset(m, nchar(as.character(f_name)) <= 3)

Answer 3

Try this:

m[!nchar(as.character(m$f_name)) > 3, ]

Answer 4

The obligatory data.table solution:

setDT(m)
m[ nchar(f_name) <= 3 ]