Question

I have a dataframe with a list of strings in it

  df$a
=========
"4343-2"
"7889-5"
"4-3456"
"334-45"
"8765-4"

I’d like to perform a string operation on the list to remove the dash sign, so I did this..

df$a <- lapply(df$a, sub, "-","", df$a)

..which only produces a set of completely empty strings. What did I get wrong?

Answer 1

you can just use sub directly.

df$a <- sub('-', '', df$a)

Instead of the convoluted lapply you’re doing since sub is “vectorized”. You can also use gsub if you think there may be more than one dash per entry.