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Infix Operator Helpers

Source: R/infix.r
suppr-infix.Rd

Infix operators for common tasks.

%''% and %""% return the right-hand side if the left-hand side is an empty string ("").

%!||% returns the right-hand side if the left-hand side is not NULL.

%0% returns the right-hand side if the left-hand side has length 0.

%allin% returns TRUE if all elements of the left-hand side are in the right-hand side.

%anyin% returns TRUE if any elements of the left-hand side are in the right-hand side.

%nonein% returns TRUE if none of the elements of the left-hand side are in the right-hand side.

%onein% returns TRUE if exactly one element of the left-hand side is in the right-hand side.

%notin% returns TRUE for elements of the left-hand side that are not in the right-hand side. This is implemented in the same way as base R and will be replaced by the base version in the R versions that have it.

Usage

lhs %''% rhs

lhs %""% rhs

lhs %!||% rhs

lhs %0% rhs

x %allin% table

x %anyin% table

x %nonein% table

x %onein% table

x %notin% table

Arguments

lhs

left-hand side object.

rhs

right-hand side object.

x

vector or NULL: the values to be matched. Long vectors are supported.

table

vector or NULL: the values to be matched against. Long vectors are not supported.

Value

For the non-%*in% operators, either the left-hand side or right-hand side, depending on the result of the operator.

For %allin%, %anyin%, %nonein%, and %onein% a single logical value (or empty logical if x has length 0) is returned. For %notin%, a logical vector of the same length as x is returned.

Details

The %*in% operators follow the semantics of %in% for NULL values:

  • Singular NULL's on the lhs always returns a length 0 logical vector.

  • NULL elements are not considered equal to singular NULL's so will give a TRUE for %nonein% and %notin% and FALSE for %allin%, %anyin% and %onein%.

See %in% semantics:

NULL %in% NULL
#> logical(0)
NULL %in% list(1, NULL)
#> logical(0)
list(1, NULL) %in% NULL
#> [1] FALSE FALSE
list(1, NULL) %in% list(1, NULL)
#> [1] TRUE TRUE

Examples

"" %''% "default" # if lhs is "", return rhs
#> [1] "default"

NULL %!||% "default" # if lhs is NULL, return *lhs* (NULL)
#> NULL
# useful for when using NULL as a default value
# or when using elements of a list that may be NULL
# e.g.,
lst <- list(a = 1, b = 2)
x <- lst$nope %!||% mean(lst$nope) # returns NULL

integer(0) %0% 5L # if lhs is length 0, return rhs
#> [1] 5

c(1, 2, 3) %allin% c(1, 2, 3, 4) # TRUE
#> [1] TRUE

c(1, 2, 3) %anyin% c(1, 2, 3, 4) # TRUE
#> [1] TRUE

c(1, 2, 3) %nonein% c(4, 5, 6) # TRUE
#> [1] TRUE

c(1, 2, 3) %onein% c(1, 4, 5) # TRUE
#> [1] TRUE

c(1, 2, 3) %notin% c(4, 5, 6) # TRUE
#> [1] TRUE TRUE TRUE