R: Negate a predicate function.

negate {purrr} | R Documentation

## Negate a predicate function.

### Description

Negate a predicate function.

### Usage

    negate(.p, .default = FALSE)

### Arguments

`.p` | A single predicate function, a formula describing such a predicate function, or a logical vector of the same length as `.x`. Alternatively, if the elements of `.x` are themselves lists of objects, a string indicating the name of a logical element in the inner lists. Only those elements where `.p` evaluates to `TRUE` will be modified.
`.default` | Optional additional argument for extractor functions (i.e. when `.f` is character, integer, or list). Returned when value is absent (does not exist) or empty (has length 0). `.null` is deprecated; please use `.default` instead.

### Value

A new predicate function.

### Examples

    negate("x")
    negate(is.null)
    negate(~ .x > 0)

    x <- transpose(list(x = 1:10, y = rbernoulli(10)))
    x %>% keep("y") %>% length()
    x %>% keep(negate("y")) %>% length()
    # Same as
    x %>% discard("y") %>% length()

[Package purrr version 0.2.4 Index]