在数据框的列上使用 sapply？ - R

Question

I have the this data frame:

df=data.frame("fg"=c("bv65","bv89"),"gh"=c(87,21))

and I need to delete the substring "bv" in the column "fg". I did it this way:

sapply(df$fg,FUN=gsub(pattern="bv",replacement = "",x=df$fg))

but I get this error:

Error in match.fun(FUN): 'gsub(pattern = "bv", replacement = "", x = df$fg)' is not a function, character or symbol

Why?

Answer 1

sub / gsub are vectorized. You can use them for all the values in the column. Perhaps, you might also want to convert the values to numeric.

df$fg <- as.numeric(sub('bv', '', df$fg))
df
#  fg gh
#1 65 87
#2 89 21

Answer 2

Ronak's solution is the way to go since gsub() / sub() can deal with vectors. But in case you wanted to know what was missing from your current approach:

sapply(df$fg, FUN = function(x) sub(pattern="bv", replacement="", x))
# Or simply
sapply(df$fg, sub, pattern="bv", replacement="")