Methods to Replace Subsets using R's Native Modification Semantics
Source:R/generic_mod.R
generic_mod.RdMethods to replace subsets.
Atomic objects are modified using R's native Modification semantics.
Recursive objects are modified via a careful shallow (not deep) copy.
Usage
ii_mod(
x,
i = NULL,
use = 1,
...,
rp,
tf,
env = NULL,
chkdup = getOption("squarebrackets.chkdup", FALSE)
)
ss_mod(
x,
s = NULL,
use = Inf,
...,
rp,
tf,
env = NULL,
chkdup = getOption("squarebrackets.chkdup", FALSE)
)
tt_mod(
x,
row = NULL,
col = NULL,
use = 1:2,
...,
rp,
tf,
env = NULL,
chkdup = getOption("squarebrackets.chkdup", FALSE)
)Arguments
- x
- i, use, s, row, col
See squarebrackets_index_args.
An empty index selection returns the original object unchanged.- ...
- rp, tf, env
- chkdup
![[for performance: set to FALSE]](figures/for_performance-set_to_FALSE-red.svg)
Details
Method Dispatch
Method dispatching is handled primarily through R's own [<- method dispatch.
The exception is data.frames, wh
Transform or Replace
Specifying argument tf will transform the subset.
Specifying rp will replace the subset.
One cannot specify both tf and rp. It's either one set or the other.
Examples
# atomic objects ====
gen_mat <- function() {
obj <- matrix(1:16, ncol = 4)
colnames(obj) <- c("a", "b", "c", "a")
return(obj)
}
obj <- obj2 <- gen_mat()
print(obj)
#> a b c a
#> [1,] 1 5 9 13
#> [2,] 2 6 10 14
#> [3,] 3 7 11 15
#> [4,] 4 8 12 16
ss_mod(obj, n(1:3), 1:ndim(obj), rp = -1:-9)
print(obj2)
#> a b c a
#> [1,] 1 5 9 13
#> [2,] 2 6 10 14
#> [3,] 3 7 11 15
#> [4,] 4 8 12 16
# above is like x[1:3, 1:3] <- -1:-9
obj <- obj2 <- gen_mat()
obj
#> a b c a
#> [1,] 1 5 9 13
#> [2,] 2 6 10 14
#> [3,] 3 7 11 15
#> [4,] 4 8 12 16
ss_mod(obj, n("a"), 2L, rp = cbind(-1:-4, -5:-8))
print(obj2)
#> a b c a
#> [1,] 1 5 9 13
#> [2,] 2 6 10 14
#> [3,] 3 7 11 15
#> [4,] 4 8 12 16
# above is like x[, "a"] <- cbind(-1:-4, -5:-8)
obj <- obj2 <- gen_mat()
obj
#> a b c a
#> [1,] 1 5 9 13
#> [2,] 2 6 10 14
#> [3,] 3 7 11 15
#> [4,] 4 8 12 16
ss_mod(obj, n(1:3), 1:ndim(obj), tf = \(x) -x)
print(obj2)
#> a b c a
#> [1,] 1 5 9 13
#> [2,] 2 6 10 14
#> [3,] 3 7 11 15
#> [4,] 4 8 12 16
# above is like x[1:3, 1:3] <- -1 * x[1:3, 1:3]
obj <- obj2 <- gen_mat()
obj
#> a b c a
#> [1,] 1 5 9 13
#> [2,] 2 6 10 14
#> [3,] 3 7 11 15
#> [4,] 4 8 12 16
ss_mod(obj, "a", 2L, tf = \(x) -x)
obj2
#> a b c a
#> [1,] 1 5 9 13
#> [2,] 2 6 10 14
#> [3,] 3 7 11 15
#> [4,] 4 8 12 16
# above is like x[, "a"] <- -1 * x[, "a"]
gen_array <- function() {
as.mutatomic(array(1:64, c(4,4,3)))
}
obj <- obj2 <- gen_array()
obj
#> , , 1
#>
#> [,1] [,2] [,3] [,4]
#> [1,] 1 5 9 13
#> [2,] 2 6 10 14
#> [3,] 3 7 11 15
#> [4,] 4 8 12 16
#>
#> , , 2
#>
#> [,1] [,2] [,3] [,4]
#> [1,] 17 21 25 29
#> [2,] 18 22 26 30
#> [3,] 19 23 27 31
#> [4,] 20 24 28 32
#>
#> , , 3
#>
#> [,1] [,2] [,3] [,4]
#> [1,] 33 37 41 45
#> [2,] 34 38 42 46
#> [3,] 35 39 43 47
#> [4,] 36 40 44 48
#>
#> mutatomic
#> typeof: integer
ss_mod(obj, n(1:3, 1:2, c(1, 3)), 1:3, rp = -1:-12)
print(obj2)
#> , , 1
#>
#> [,1] [,2] [,3] [,4]
#> [1,] 1 5 9 13
#> [2,] 2 6 10 14
#> [3,] 3 7 11 15
#> [4,] 4 8 12 16
#>
#> , , 2
#>
#> [,1] [,2] [,3] [,4]
#> [1,] 17 21 25 29
#> [2,] 18 22 26 30
#> [3,] 19 23 27 31
#> [4,] 20 24 28 32
#>
#> , , 3
#>
#> [,1] [,2] [,3] [,4]
#> [1,] 33 37 41 45
#> [2,] 34 38 42 46
#> [3,] 35 39 43 47
#> [4,] 36 40 44 48
#>
#> mutatomic
#> typeof: integer
# above is like x[1:3, , 1:2] <- -1:-12
#############################################################################
# lists ====
obj <- list(a = 1:10, b = letters[1:11], c = 11:20)
print(obj)
#> $a
#> [1] 1 2 3 4 5 6 7 8 9 10
#>
#> $b
#> [1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k"
#>
#> $c
#> [1] 11 12 13 14 15 16 17 18 19 20
#>
ii_mod(obj, "a", rp = list(1L))
print(obj)
#> $a
#> [1] 1
#>
#> $b
#> [1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k"
#>
#> $c
#> [1] 11 12 13 14 15 16 17 18 19 20
#>
# above is equivalent to obj[["a"]] <- 1L; obj
obj <- list(a = 1:10, b = letters[1:11], c = 11:20)
ii_mod(obj, is.numeric, rp = list(-1:-10, -11:-20))
print(obj)
#> $a
#> [1] -1 -2 -3 -4 -5 -6 -7 -8 -9 -10
#>
#> $b
#> [1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k"
#>
#> $c
#> [1] -11 -12 -13 -14 -15 -16 -17 -18 -19 -20
#>
# above is equivalent to obj[which(sapply(obj, is.numeric))] <- list(-1:-10, -11:-20); obj
obj <- rbind(
lapply(1:4, \(x)sample(c(TRUE, FALSE, NA))),
lapply(1:4, \(x)sample(1:10)),
lapply(1:4, \(x)rnorm(10)),
lapply(1:4, \(x)sample(letters))
)
colnames(obj) <- c("a", "b", "c", "a")
print(obj)
#> a b c a
#> [1,] logical,3 logical,3 logical,3 logical,3
#> [2,] integer,10 integer,10 integer,10 integer,10
#> [3,] numeric,10 numeric,10 numeric,10 numeric,10
#> [4,] character,26 character,26 character,26 character,26
ss_mod(obj, n(1:3), 1:ndim(obj),rp = n(-1))
print(obj)
#> a b c a
#> [1,] -1 -1 -1 logical,3
#> [2,] -1 -1 -1 integer,10
#> [3,] -1 -1 -1 numeric,10
#> [4,] character,26 character,26 character,26 character,26
# above is equivalent to obj[1:3, 1:3] <- list(-1)
ii_mod(obj, is.numeric, rp = n(-1))
print(obj)
#> a b c a
#> [1,] -1 -1 -1 logical,3
#> [2,] -1 -1 -1 -1
#> [3,] -1 -1 -1 -1
#> [4,] character,26 character,26 character,26 character,26
# above is equivalent to obj[sapply(obj, is.numeric)] <- list(-1)
ss_mod(obj, n("a"), 2L, rp = n(-1))
print(obj)
#> a b c a
#> [1,] -1 -1 -1 -1
#> [2,] -1 -1 -1 -1
#> [3,] -1 -1 -1 -1
#> [4,] -1 character,26 character,26 -1
# above is equivalent to
# obj[, lapply(c("a", "a"), \(i) which(colnames(obj) == i)) |> unlist()] <- list(-1)
obj <- array(as.list(1:64), c(4,4,3))
print(obj)
#> , , 1
#>
#> [,1] [,2] [,3] [,4]
#> [1,] 1 5 9 13
#> [2,] 2 6 10 14
#> [3,] 3 7 11 15
#> [4,] 4 8 12 16
#>
#> , , 2
#>
#> [,1] [,2] [,3] [,4]
#> [1,] 17 21 25 29
#> [2,] 18 22 26 30
#> [3,] 19 23 27 31
#> [4,] 20 24 28 32
#>
#> , , 3
#>
#> [,1] [,2] [,3] [,4]
#> [1,] 33 37 41 45
#> [2,] 34 38 42 46
#> [3,] 35 39 43 47
#> [4,] 36 40 44 48
#>
ss_mod(obj, n(1:3, 1:2), c(1,3), rp = as.list(-1:-24))
print(obj)
#> , , 1
#>
#> [,1] [,2] [,3] [,4]
#> [1,] -1 -4 -7 -10
#> [2,] -2 -5 -8 -11
#> [3,] -3 -6 -9 -12
#> [4,] 4 8 12 16
#>
#> , , 2
#>
#> [,1] [,2] [,3] [,4]
#> [1,] -13 -16 -19 -22
#> [2,] -14 -17 -20 -23
#> [3,] -15 -18 -21 -24
#> [4,] 20 24 28 32
#>
#> , , 3
#>
#> [,1] [,2] [,3] [,4]
#> [1,] 33 37 41 45
#> [2,] 34 38 42 46
#> [3,] 35 39 43 47
#> [4,] 36 40 44 48
#>
# above is equivalent to obj[1:3, , 1:2] <- as.list(-1:-24)
obj <- array(as.list(1:64), c(4,4,3))
ii_mod(obj, i = \(x) x <= 5, rp = as.list(-1:-5))
print(obj)
#> , , 1
#>
#> [,1] [,2] [,3] [,4]
#> [1,] -1 -5 9 13
#> [2,] -2 6 10 14
#> [3,] -3 7 11 15
#> [4,] -4 8 12 16
#>
#> , , 2
#>
#> [,1] [,2] [,3] [,4]
#> [1,] 17 21 25 29
#> [2,] 18 22 26 30
#> [3,] 19 23 27 31
#> [4,] 20 24 28 32
#>
#> , , 3
#>
#> [,1] [,2] [,3] [,4]
#> [1,] 33 37 41 45
#> [2,] 34 38 42 46
#> [3,] 35 39 43 47
#> [4,] 36 40 44 48
#>
# above is equivalent to obj[sapply(onj, \(x) x <= 5)] <- as.list(-1:-5)
#############################################################################
# data.frame-like objects - whole columns ====
obj <- data.frame(a = 1:10, b = letters[1:10], c = 11:20, d = factor(letters[1:10]))
str(obj) # notice that columns "a" and "c" are INTEGER (`int`)
#> 'data.frame': 10 obs. of 4 variables:
#> $ a: int 1 2 3 4 5 6 7 8 9 10
#> $ b: chr "a" "b" "c" "d" ...
#> $ c: int 11 12 13 14 15 16 17 18 19 20
#> $ d: Factor w/ 10 levels "a","b","c","d",..: 1 2 3 4 5 6 7 8 9 10
tt_mod(
obj, col = is.numeric,
tf = sqrt
)
#############################################################################
# data.frame-like objects - partial columns ====
obj <- data.frame(a = 1:10, b = letters[1:10], c = 11:20, d = factor(letters[1:10]))
str(obj) # notice that columns "a" and "c" are INTEGER (`int`)
#> 'data.frame': 10 obs. of 4 variables:
#> $ a: int 1 2 3 4 5 6 7 8 9 10
#> $ b: chr "a" "b" "c" "d" ...
#> $ c: int 11 12 13 14 15 16 17 18 19 20
#> $ d: Factor w/ 10 levels "a","b","c","d",..: 1 2 3 4 5 6 7 8 9 10
tt_mod(
obj, with(obj, (a > 2) & (c < 17)), is.numeric,
tf = sqrt
)
tt_mod(
obj, with(obj, (a > 2) & (c < 17)), is.numeric,
tf = sqrt
)
tt_mod(
obj, with(obj, (a > 2) & (c < 17)), is.numeric,
tf = sqrt
)