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Is variable nested within another variable?

Source: R/nested.R
is_nested.Rd

This function checks if a variable is nested within another variable. If the levels in the first variable appear only within the levels of the second variable, it returns TRUE; otherwise, it returns FALSE. The function can also handle NA values based on the na.rm parameter.

Usage

is_nested(x, y, na.rm = TRUE, ignore = c("constant", "unique", "bijective"))

Arguments

x, y

Vectors of the same size where x (child variable) is nested in y (parent variable)

na.rm

Remove NA values when checking for nestedness.

ignore

A character vector of trivial cases of nesting to ignore, i.e. not count as nested. Any of "constant" (x or y has a single value), "unique" (x has all unique values) and "bijective" (x and y have a one-to-one correspondence). Use NULL to count all cases.

Value

TRUE if the values in vector x are nested within vector y, FALSE otherwise. It is also FALSE for any trivial case listed in ignore.

Details

By default, trivial cases of nesting are not counted and it returns FALSE when x or y is constant (has a single value), x has all unique values, or x and y are bijective (have a one-to-one correspondence). Use ignore to choose which of these cases are not counted.

Examples

df <- data.frame(
  site = rep(c("A", "B"), each = 4),
  plot1 = rep(c("A1", "A2", "B1", "B2"), each = 2),
  plot2 = rep(c("A1", "A2", "A1", "A2"), each = 2)
)
is_nested(df$plot1, df$site) # TRUE
#> [1] TRUE
is_nested(df$plot2, df$site) # FALSE since A1 and A2 appear in both sites
#> [1] FALSE
df$id <- seq_len(nrow(df))
is_nested(df$id, df$site) # FALSE since id has all unique values
#> [1] FALSE
is_nested(df$id, df$site, ignore = c("constant", "bijective")) # TRUE
#> [1] TRUE