I have a vector of value:
y=c(2,3,4,4,3,2,1,1)
And a list of vector of positions:
l=list(c(1,2),c(2,3),c(3,4),c(4,5),c(5,6),c(6,7),c(7,8),c(8,1))
I'd like to replace the value of y
by NAs (or other) for each of the element in the list l
.
Expected output is a list of length length(l)
:
[[1]]
[1] NA NA 4 4 3 2 1 1
[[2]]
[1] 2 NA NA 4 3 2 1 1
[[3]]
[1] 2 3 NA NA 3 2 1 1
[[4]]
[1] 2 3 4 NA NA 2 1 1
[[5]]
[1] 2 3 4 4 NA NA 1 1
[[6]]
[1] 2 3 4 4 3 NA NA 1
[[7]]
[1] 2 3 4 4 3 2 NA NA
[[8]]
[1] NA 3 4 4 3 2 1 NA
Base R solutions are preferred.
CodePudding user response:
We could either loop over the list
, use the index to replace
the values of 'y' to NA
lapply(l, \(x) replace(y, x, NA))
[[1]]
[1] NA NA 4 4 3 2 1 1
[[2]]
[1] 2 NA NA 4 3 2 1 1
[[3]]
[1] 2 3 NA NA 3 2 1 1
[[4]]
[1] 2 3 4 NA NA 2 1 1
[[5]]
[1] 2 3 4 4 NA NA 1 1
[[6]]
[1] 2 3 4 4 3 NA NA 1
[[7]]
[1] 2 3 4 4 3 2 NA NA
[[8]]
[1] NA 3 4 4 3 2 1 NA
Or another option is is.na<-
lapply(l, `is.na<-`, x = y)
[[1]]
[1] NA NA 4 4 3 2 1 1
[[2]]
[1] 2 NA NA 4 3 2 1 1
[[3]]
[1] 2 3 NA NA 3 2 1 1
[[4]]
[1] 2 3 4 NA NA 2 1 1
[[5]]
[1] 2 3 4 4 NA NA 1 1
[[6]]
[1] 2 3 4 4 3 NA NA 1
[[7]]
[1] 2 3 4 4 3 2 NA NA
[[8]]
[1] NA 3 4 4 3 2 1 NA
CodePudding user response:
Here is a base R solution with lapply
.
lapply(l, \(x) {is.na(y) <- x; y})
#[[1]]
#[1] NA NA 4 4 3 2 1 1
#
#[[2]]
#[1] 2 NA NA 4 3 2 1 1
#
#[[3]]
#[1] 2 3 NA NA 3 2 1 1
#
#[[4]]
#[1] 2 3 4 NA NA 2 1 1
#
#[[5]]
#[1] 2 3 4 4 NA NA 1 1
#
#[[6]]
#[1] 2 3 4 4 3 NA NA 1
#
#[[7]]
#[1] 2 3 4 4 3 2 NA NA
#
#[[8]]
#[1] NA 3 4 4 3 2 1 NA