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Check that values are absent

Source: R/not_in.R
not_in.Rd

Check that values from one vector are absent from another vector

Usage

not_in(x, table, value = TRUE)

Arguments

x

Vector or factor with values to test absence from table. x should not be of type double.

table

Vector or factor in which to test for absence of x. table should not be of type double.

value

TRUE or FALSE: should a vector with values be returned instead of a boolean vector?

Value

If value is TRUE: the values in x that are absent from table, with a zero-length object of the same type as x, e.g., character(0) or logical(0) if none of the values in x are absent from table (i.e., all are present in table). If value is FALSE: a boolean vector indicating for each element in x if it is absent from table.

Details

Duplicates in x are kept, in contrast to setdiff(), see the Examples.

Factor-input to x is converted to character, to prevent returning a factor with all values of x as levels.

Zero-length input behaves slightly different from other values: not_in() returns logical(0) for zero-length input to x if that is absent from table if value is FALSE. If value is TRUE, the behaviour is normal: returning x.

NA is allowed in x and table and behaves the same as other values: the returned NA (if value is TRUE) and the returned zero-length value (if value is FALSE) have the same type as the NA in x if NA is absent from table. NAs of different types in x and table match each other.

Names are not considered when matching but are retained in the output, similar to %in%.

Programming notes

not_in() does not allow input of type double because matching such input should allow for small numerical errors by using a tolerance, for example, as the error message indicates, using are_equal().

Apart from not allowing numeric input, not_in(x, table, value = FALSE) is equivalent to x %notin% table, where %notin% is a function in base R since version 4.6.0.

See also

setdiff() for a similar function which removes duplicates; are_equal() to match numeric input using a tolerance; identical(), not_in() and match() (containing %in% and, from R 4.6.0 onwards, '%notin%') to check for exact (in)equality, with Comparison to do so using binary operators

Other functions to check equality: are_equal(), check_case(), get_file_path(), replace_vals()

Examples

x <- letters[1:4]
table <- letters[3:6]
not_in(x, table) # c("a", "b")
#> [1] "a" "b"
not_in(as.factor(x), as.factor(table)) # c("a", "b")
#> [1] "a" "b"
# c(TRUE, TRUE, FALSE, FALSE), same as !(x %in% table):
not_in(x, table, value = FALSE)
#> [1]  TRUE  TRUE FALSE FALSE

x_dupl <- c(x, letters[c(2, 4:6, 5)])
table_dupl <- letters[c(3:8, 5:7)]
not_in(x_dupl, table_dupl) # c("a", "b", "b")
#> [1] "a" "b" "b"
setdiff(x_dupl, table_dupl) # c("a", "b")
#> [1] "a" "b"
not_in(x_dupl, table_dupl, value = FALSE)
#> [1]  TRUE  TRUE FALSE FALSE  TRUE FALSE FALSE FALSE FALSE
# c(TRUE, TRUE, FALSE, FALSE, TRUE, FALSE, FALSE, FALSE, FALSE)

# Names are not considered when matching but are retained in the output
not_in(c(x = "c", y = "b", z = "a"), c(a = "a", b = "b"))
#>   x 
#> "c"