How do I replace NA values with zeros in an R dataframe?

Question

I have a data frame and some columns have NA values.

How do I replace these NA values with zeroes?

Answer 1

dplyr example:

library(dplyr)

df1 <- df1 %>%
    mutate(myCol1 = if_else(is.na(myCol1), 0, myCol1))

Note: This works per selected column, if we need to do this for all column, see @reidjax's answer using mutate_each.