R Replace NA for all Columns Except * - r

Question

library(tidyverse)
df <- tibble(Date = c(rep(as.Date("2020-01-01"), 3), NA),
col1 = 1:4,
thisCol = c(NA, 8, NA, 3),
thatCol = 25:28,
col999 = rep(99, 4))
#> # A tibble: 4 x 5
#> Date col1 thisCol thatCol col999
#> <date> <int> <dbl> <int> <dbl>
#> 1 2020-01-01 1 NA 25 99
#> 2 2020-01-01 2 8 26 99
#> 3 2020-01-01 3 NA 27 99
#> 4 NA 4 3 28 99
My actual R data frame has hundreds of columns that aren't neatly named, but can be approximated by the df data frame above.
I want to replace all values of NA with 0, with the exception of several columns (in my example I want to leave out the Date column and the thatCol column. I'd want to do it in this sort of fashion:
df %>% replace(is.na(.), 0)
#> Error: Assigned data `values` must be compatible with existing data.
#> i Error occurred for column `Date`.
#> x Can't convert <double> to <date>.
#> Run `rlang::last_error()` to see where the error occurred.
And my unsuccessful ideas for accomplishing the "everything except" replace NA are shown below.
df %>% replace(is.na(c(., -c(Date, thatCol)), 0))
df %>% replace_na(list([, c(2:3, 5)] = 0))
df %>% replace_na(list(everything(-c(Date, thatCol)) = 0))
Is there a way to select everything BUT in the way I need to? There's hundred of columns, named inconsistently, so typing them one by one is not a practical option.

Answer 1

You can use mutate_at :
library(dplyr)
Remove them by Name
df %>% mutate_at(vars(-c(Date, thatCol)), ~replace(., is.na(.), 0))
Remove them by position
df %>% mutate_at(-c(1,4), ~replace(., is.na(.), 0))
Select them by name
df %>% mutate_at(vars(col1, thisCol, col999), ~replace(., is.na(.), 0))
Select them by position
df %>% mutate_at(c(2, 3, 5), ~replace(., is.na(.), 0))
If you want to use replace_na
df %>% mutate_at(vars(-c(Date, thatCol)), tidyr::replace_na, 0)
Note that mutate_at is soon going to be replaced by across in dplyr 1.0.0.

Answer 2

You have several options here based on data.table.
One of the coolest options: setnafill (version >= 1.12.4):
library(data.table)
setDT(df)
data.table::setnafill(df,fill = 0, cols = colnames(df)[!(colnames(df) %in% c("Date", thatCol)]))
Note that your dataframe is updated by reference.

Answer 3

Another base solution:
to_change<-grep("^(this|col)",names(df))
df[to_change]<- sapply(df[to_change],function(x) replace(x,is.na(x),0))
df
# A tibble: 4 x 5
Date col1 thisCol thatCol col999
<date> <dbl> <dbl> <int> <dbl>
1 2020-01-01 1 0 25 99
2 2020-01-01 2 8 26 99
3 2020-01-01 3 0 27 99
4 NA 0 3 28 99
Data(I changed one value):
df <- structure(list(Date = structure(c(18262, 18262, 18262, NA), class = "Date"),
col1 = c(1L, 2L, 3L, NA), thisCol = c(NA, 8, NA, 3), thatCol = 25:28,
col999 = c(99, 99, 99, 99)), row.names = c(NA, -4L), class = c("tbl_df",
"tbl", "data.frame"))

Answer 4

replace works on a data.frame, so we can just do the replacement by index and update the original dataset
df[-c(1, 4)] <- replace(df[-c(1, 4)], is.na(df[-c(1, 4)]), 0)
Or using replace_na with across (from the new dplyr)
library(dplyr)
library(tidyr)
df %>%
mutate(across(-c(Date, thatCol), ~ replace_na(., 0)))

Answer 5

If you know the ones that you don't want to change, you could do it like this:
df <- tibble(Date = c(rep(as.Date("2020-01-01"), 3), NA),
col1 = 1:4,
thisCol = c(NA, 8, NA, 3),
thatCol = 25:28,
col999 = rep(99, 4))
#dplyr
df_nonreplace <- select(df, c("Date", "thatCol"))
df_replace <- df[ ,!names(df) %in% names(df_nonreplace)]
df_replace[is.na(df_replace)] <- 0
df <- cbind(df_nonreplace, df_replace)
> head(df)
Date thatCol col1 thisCol col999
1 2020-01-01 25 1 0 99
2 2020-01-01 26 2 8 99
3 2020-01-01 27 3 0 99
4 <NA> 28 4 3 99