从向量中删除某些值

Question

我有一个包含一些字符的向量：

结构glimpse(a)

List of 5
 $ : chr [1:2] "Thai" "Restaurants"
 $ : chr [1:2] "Vietnamese" "Restaurants"
 $ : chr [1:3] "Restaurants" "Vegetarian" "Indian"
 $ : chr [1:5] "Nightlife" "Bars" "Restaurants" "Thai" ...
 $ : chr [1:4] "Asian Fusion" "Chinese" "Japanese" "Restaurants"

这是一个dput(a)

list(c("Thai", "Restaurants"), c("Vietnamese", "Restaurants"), 
    c("Restaurants", "Vegetarian", "Indian"), c("Nightlife", 
    "Bars", "Restaurants", "Thai", "Sports Bars"), c("Asian Fusion", 
    "Chinese", "Japanese", "Restaurants"))

我想通过排除来丢弃一些值。例如，下面的值是应该留在向量中的唯一值。所有其他值都应该删除，不能替换。

c("Chinese", "Japanese", "Sushi Bars", "Indian", "Thai", "Vietnamese", "Korean","Taiwanese", "Malaysian", "Mongolian", "Indonesian", "Laotian", "Myanmar", "Pan Asian", "Tempura", "Wok")

因此，我尝试了本文中的解决方案：How to delete multiple values from a vector?

所以我就这么做了：

rm <-  c("Chinese", "Japanese", "Sushi Bars", "Indian", "Thai", "Vietnamese", "Korean","Taiwanese", "Malaysian", "Mongolian", "Indonesian", "Laotian", "Myanmar", "Pan Asian", "Tempura", "Wok")

a [! a %in% rm]

但是一切都没有改变吗？！如何从a中删除那些不属于rm的值