Search code examples
rcombinations

Find all combinations of words in a vector

I have a vector of words:

str <- c("The", "Cat", "Jumped")

I would like to find all combinations of words and insert a "+" between any combinations of more than one, similar to:

paste(str, collapse = " + ")
# [1] "The + Cat + Jumped"

My desired output would be:

want <- c("The", "Cat", "Jumped", 
          "The + Cat", "The + Jumped",
          "Cat + Jumped",
          "The + Cat + Jumped")

Also note I need only combinations so order doesn't matter and either "The + Cat" or "Cat + The" is fine, but I do not want both.

I tried some approaches with combn (here), outer (here), expand.grid (here), and following @Akrun's suggestion on a similar question r - Get different combinations of words but to no avail.

Solution 
  • unlist(lapply(seq(str), combn, x=str, paste, collapse=' + '))

[1] "The"                "Cat"                "Jumped"             "The + Cat"          "The + Jumped"      
[6] "Cat + Jumped"       "The + Cat + Jumped"