Question

I would like to replace all NA values in numeric columns in my data frame with 0. How should I go about it?

I come as far as getting a list of numeric variables with NA values as follows (I am sure it is not optimal):

iris[3,4] <- NA
missingVars <- iris[colSums(is.na(iris)) > 0] 
missingNumVars <- missingVars[sapply(missingVars, is.numeric)]

Answer 1

Something like this will work and avoid the duplicate copies of an object of the same size iris (created by is.na(iris))

as.data.frame(lapply(iris, function(x) 
if(is.numeric(x)) {return(replace(x, is.na(x),0))} 
  else {return(x)}) )