R: How to split a string into values and map the r

问题:

This question already has an answer here:

• Split a column of concatenated comma-delimited data and recode output as factors 2 answers

As shown in the above pic, I've a column, genres, with a list of genres the corresponding movie belongs to. There are in total 19 unique genres. I'd like to know if I can manipulate this data into appending 19 columns to the data set each corresponding to each of the genres identifiers and label the corresponding cells as 0 or 1 indicating the movies affiliation to the each genre columns.

It should look something like below picture.

回答1:

We can do this after splitting the 'genres' column

library(qdapTools)
d1 <- mtabulate(strsplit(as.character(df1$genres),","))
row.names(d1) <- sub("\\s*\\(.*", "", df1$title)

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Or another option is to create a matrix with column names as 'genres' and then do a comparison on the splitted string

m1 <- matrix(0, dimnames = list(sub("\\s*\\(.*", "", df1$title), 
      c("Adventure", "Animation", "Children",
   "Comedy", "Fantasy", "Romance", "Action", "Crime", "Thriller")), ncol=9, nrow = nrow(df1))
m1 + (t(sapply(strsplit(as.character(df1$genres), ","), function(x) colnames(m1) %in% x)))
#         Adventure Animation Children Comedy Fantasy Romance Action Crime Thriller
#Toy Story         1         1        1      1       1       0      0     0        0
#Jumanji           1         0        1      0       1       0      0     0        0
#Heat              0         0        0      0       0       0      1     1        1