bic ton - 1 year ago 96
R Question

# How to deal with NA in two lists?

I have two lists and I want make them consistent in terms of

`NA`
. Put NA Whenever there is NA in one of the two lists without changing in anything else in the structure of the list.

``````set.seed(123)
m1 <- matrix(nrow=2,ncol=2,data=runif(4))
m1[1,1] <- NA
m2 <- matrix(nrow=2,ncol=2,data=runif(4))
m2[1,2] <- NA
lis <- list(m1, m2)
m1 <- matrix(nrow=2,ncol=2,data=runif(4))
m2 <- matrix(nrow=2,ncol=2,data=runif(4))
m2[2,1] <- NA
bis <- list(m1, m2)
``````

I tried this but with no success
`bis[is.na(lis)]=NA`

Desired output:

``````  > lis
[[1]]
[,1]      [,2]
[1,]        NA 0.9568333
[2,] 0.4566147 0.4533342

[[2]]
[,1]     [,2]
[1,] 0.9404673       NA
[2,] 0.0455565       NA

> bis
[[1]]
[,1]      [,2]
[1,]        NA 0.9568333
[2,] 0.4566147 0.4533342

[[2]]
[,1]        [,2]
[1,] 0.6775706        NA
[2,] 0.5726334        NA
``````

Here's an option:

``````z <- Map("|", lapply(lis, is.na), lapply(bis, is.na))
bis <- Map(function(mat, idx) {mat[idx] <- NA; mat}, bis, z)
lis <- Map(function(mat, idx) {mat[idx] <- NA; mat}, lis, z)
``````

However, there may be faster / more efficient approaches due to the numerous `Map` and `lapply` calls.

For the case of >2 lists you can use the following approach (assuming that each list has the same length):

``````# create a named list - naming is important if you want to
# assign them back to the global environment later on
mylist <- list(lis = lis, bis = bis, kis = kis)

n <- max(lengths(mylist))
z <- lapply(1:n, function(i) {
Reduce(`+`, Map(function(y) is.na(y[[i]]), mylist))>0
})

mylist <- lapply(mylist, function(mat) {
Map(function(m, idx) {m[idx] <- NA; m}, mat, z)
})

# to assign them back to the global environment, run:
list2env(mylist, envir = .GlobalEnv)
``````

Now your original lists are modified in the global environment.

Sample data:

``````set.seed(123)
n <- 4
lis <- list(
m1 = matrix(nrow=n,ncol=n,data=sample(c(NA, 1:10), n*n, TRUE)),
m2 = matrix(nrow=n,ncol=n,data=sample(c(NA, 1:10), n*n, TRUE))
)
bis <- list(
m1 = matrix(nrow=n,ncol=n,data=sample(c(NA, 1:10), n*n, TRUE)),
m2 = matrix(nrow=n,ncol=n,data=sample(c(NA, 1:10), n*n, TRUE))
)
kis <- list(
m1 = matrix(nrow=n,ncol=n,data=sample(c(NA, 1:10), n*n, TRUE)),
m2 = matrix(nrow=n,ncol=n,data=sample(c(NA, 1:10), n*n, TRUE))
)
``````
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