purrr: head_while – R documentation

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head_while

Find head/tail that all satisfies a predicate.

Find head/tail that all satisfies a predicate.

head_while(.x, .p, ...)

tail_while(.x, .p, ...)

`.x`	A list or atomic 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 logical element in the inner lists. Only those elements where `.p` evaluates to `TRUE` will be modified.
`...`	Additional arguments passed on to the mapped function.

A vector the same type as .x.

pos <- function(x) x >= 0
head_while(5:-5, pos)
tail_while(5:-5, negate(pos))

big <- function(x) x > 100
head_while(0:10, big)
tail_while(0:10, big)

Functional Programming Tools

v0.3.4

GPL-3 | file LICENSE

Authors

Lionel Henry [aut, cre], Hadley Wickham [aut], RStudio [cph, fnd]

Initial release