制作与 R 中条件匹配的行向量

Question

I have a dataframe 'likes' that looks like this:

uid       Likes

123       Harry Potter
123       Fitness
123       Muesli
123       Fanta
123       Nokia
321       Harry Potter
321       Muesli
455       Harry Potter
455       Muesli
699       Muesli
123       Belgium

Furthermore I have a bunch of strings, for example: WhatLikes <- c("Harry Potter","Muesli")

I want a vector of the uid's that 'like' Harry Potter OR Muesli. Take note that WhatLikes is much bigger than this example.

The solution should thus be a vector that contains 123 , 321 , 455 , 699 .

Help me out! thanks!

Answer 1

We can use %in% to get a logical index of elements in 'Likes' that are found in 'WhatLikes'. Get the corresponding 'uid' from the dataset. Apply unique to remove the duplicate 'uid's.

unique(df1$uid[df1$Likes %in% WhatLikes])
#[1] 123 321 455 699