Add negate argument to str_subset(), str_detect(), and str_which()

[yutannihilation]

Currently, there's no cool way of doing grep -v with stringr. If I want to negate the pattern, I need to use str_detect(), but this is not handy.

library(stringr)

fruit <- c("apple", "banana", "pear", "pinapple")
fruit[!str_detect(fruit, "^p)]

On the other hand, stringi's equivalent functions have negate argument since version 1.1.1. So, it seems easy to introduce the argument in stringr package. Note that my primary motivation was str_subset(), only, but as stringi::stri_detect() also has negate, I included the equivalent functions, str_detect() and str_which().

library(stringr)

fruit <- c("apple", "banana", "pear", "pinapple")
str_subset(fruit, "^p")
#> [1] "pear"     "pinapple"

str_subset(fruit, "^p", negate = TRUE)
#> [1] "apple"  "banana"

^{Created on 2018-10-01 by the reprex package (v0.2.1)}

[hadley]

Thanks!