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Construct Indices

Source: R/ci.R
developer_ci.Rd

These functions construct indices.

  • ci_ii() constructs an integer vector flat/interior indices.

  • ci_margin() constructs an integer vector of indices for one particular dimension margin.

  • ci_ss() constructs a list of integer subscripts.

  • ci_df() is the same as ci_margin(), except it is specifically designed for data.frame-like objects.
    It is a separate function, because things like dimnames(x)[1] and rownames(x) do not always return the same output for certain data.frame-like objects.

  • ci_obs() and ci_vars() construct row and column indices, respectively, for data.frame-like objects.

Usage

ci_ii(
  x,
  i = NULL,
  use = 1L,
  chkdup = FALSE,
  uniquely_named = FALSE,
  .abortcall = sys.call()
)

ci_margin(
  x,
  slice = NULL,
  margin,
  use = 1L,
  chkdup = FALSE,
  uniquely_named = FALSE,
  .abortcall = sys.call()
)

ci_ss(
  x,
  s = NULL,
  use = 1:ndim(x),
  chkdup = FALSE,
  uniquely_named = FALSE,
  .abortcall = sys.call()
)

Arguments

x

the object for which the indices are meant.

i, s, use, slice, margin

See squarebrackets_indx_args.

chkdup

see squarebrackets_options.
[for performance: set to FALSE]

uniquely_named

Boolean, indicating if the user knows a-priori that the relevant names of x are unique.
If set to TRUE, speed may increase.
But specifying TRUE when the relevant names are not unique will result in incorrect output.

.abortcall

environment where the error message is passed to.

Value

An integer vector of constructed indices.

Examples


x <- matrix(1:25, 5, 5)
colnames(x) <- c("a", "a", "b", "c", "d")
print(x)
#>      a  a  b  c  d
#> [1,] 1  6 11 16 21
#> [2,] 2  7 12 17 22
#> [3,] 3  8 13 18 23
#> [4,] 4  9 14 19 24
#> [5,] 5 10 15 20 25

bool <- sample(c(TRUE, FALSE), 5, TRUE)
int <- 1:4
chr <- c("a", "a")
tci_bool(bool, nrow(x))
#> [1] 2
tci_int(int, ncol(x), -1)
#> [1] 5
tci_chr(chr, colnames(x))
#> [1] 1 2 1 2

ci_ii(x, 1:10)
#>  [1]  1  2  3  4  5  6  7  8  9 10
ci_margin(x, 1:4, 2)
#> [1] 1 2 3 4
ci_ss(x, n(~ .bi(-1:-5), 1:4), 1:2)
#> [[1]]
#> [1] 5 4 3 2 1
#> 
#> [[2]]
#> [1] 1 2 3 4
#>