purrr (version 0.1.0)

detect: Find the value or position of the first match.

Description

Find the value or position of the first match.

Usage

detect(.x, .p, ..., .right = FALSE)
detect_index(.x, .p, ..., .right = FALSE)

Arguments

.x

A list or vector.

.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 lo

...

Additional arguments passed on to .f.

.right

If FALSE, the default, starts at the beginnging of the vector and move towards the end; if TRUE, starts at the end of the vector and moves towards the beginning.

Value

• detect the value of the first item that matches the predicate; detect_index the position of the matching item. If not found, detect returns NULL and detect_index returns 0.

Examples

is_even <- function(x) x %% 2 == 0

3:10 %>% detect(is_even)
3:10 %>% detect_index(is_even)

3:10 %>% detect(is_even, .right = TRUE)
3:10 %>% detect_index(is_even, .right = TRUE)