Clash Royale CLAN TAG#URR8PPP

Replace numeric(0) with NAs in all lists in a column of lists in r

I have a column in a dataframe that stores lists. Here is an example below:

col
1 9
2 8, 8, 8, 5
3 1, 8, 10, 4
4 3, 6, 1, 6
5 9, 9, 10, 4
6 8, 8, 9, 2
7 6, 10, 4, 7
8 6, 1, 5, 9
9 4, 7, 5, 10
10 7, 9, 2, 5


This is the code I used to generate the above example:

set.seed(123)
example <- data.frame(matrix(NA_real_, nrow=10, ncol=1))
colnames(example) <- "col"
for(y in 1:10)
example$col[y] <- list(c(c(sample(1:10,1)),c(sample(1:10,1)),c(sample(1:10,1)),c(sample(1:10,1))))


example$col[1] <- list(c(9))


I want to remove all occurrences of the number 9 from all of these lists, in this column of my data frame, to get something like this:

col
1 NA
2 8, 8, 8, 5
3 1, 8, 10, 4
4 3, 6, 1, 6
5 10, 4
6 8, 8, 2
7 6, 10, 4, 7
8 6, 1, 5
9 4, 7, 5, 10
10 7, 2, 5


instead of this, which I'm currently getting with example$col <- lapply(example$col, function(x) x[x != 9] )

example$col <- lapply(example$col, function(x) x[x != 9] )

col
1 numeric(0)
2 8, 8, 8, 5
3 1, 8, 10, 4
4 3, 6, 1, 6
5 10, 4
6 8, 8, 2
7 6, 10, 4, 7
8 6, 1, 5
9 4, 7, 5, 10
10 7, 2, 5


How can I replace the numeric(0) with NA_real_ and still be able to remove all the 9s?

numeric(0)

NA_real_

2 Answers
2

Modify your lapply statement like so

lapply

lapply(example$col, function(x) y <- x[x != 9]; if(length(y) < 1) y <- NA ; y )


As own function - makes it easier to modify in the future

remove_num <- function(vec, num)
x <- vec[vec != num]
if (length(x) < 1) x <- NA
x


lapply(example$col, remove_num, 9)


You could do both, remove the 9s and change single 9s to NA_real_, in one step with an if statement.

NA_real_

if

example$col <- lapply(example$col, function(x)
if(length(x) == 1L && x == 9) NA_real_ else x[x != 9]
)

example
# col
# 1 NA
# 2 10, 1, 6
# 3 6, 5, 10, 5
# 4 7, 6, 2
# 5 3, 1, 4, 10
# 6 7, 7, 10
# 7 7, 8, 6, 6
# 8 3, 2, 10, 10
# 9 7, 8, 1, 5
# 10 8, 3, 4, 3


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