r Separate numbers with "/" in grouped data frame

Question

I have a large dataframe that looks like the following example:

Say that there is a ball game, where you can throw the ball to hit a target and get points. There is a team A and B, and everyone can decide how many times they want to throw the ball (so this is unequal). It looks like this:

df<-data.frame("ID" = as.factor(c(1,2,3,4,5,6,7,8,9,10)),
               "Group" = c("A","A","A","A","A","B","B","B","B","B"),
               "Number_of_hits" = c(1,2,5,3,3,1,2,1,1,3),
               "Score_per_hit"=c("60","23.4/18.1","30/34.1/40/10.2/15.5","12/15.0/40","40/23.1/22","20.5","64.8/12.2","50","30","20/43.3/65"))

   ID Group Number_of_hits        Score_per_hit
   1     A              1                   60
   2     A              2            23.4/18.1
   3     A              5 30/34.1/40/10.2/15.5
   4     A              3           12/15.0/40
   5     A              3           40/23.1/22
   6     B              1                 20.5
   7     B              2            64.8/12.2
   8     B              1                   50
   9     B              1                   30
  10     B              3           20/43.3/65

Now, I would like to change it in a way that I can do something with the Scoring, so I would like it to be like this:

   ID Group Score_per_hit
   1     A          60.0
   2     A          23.4
   2     A          18.1
   3     A          30.0
   3     A          34.1
   3     A          40.0
   3     A          10.2
   3     A          15.5
   4     A          12.0
   4     A          15.0
   4     A          40.0
   5     A          40.0
   5     A          23.1
   5     A          22.0
etc..

I have seen/tried some things with str_extract but I only get errors.. Could somebody help me? It's very much appreciated!

Answer 1

There may be a more elegant way, but here is an option using a for loop:

df2 <- vector("list", nrow(df))
for(i in seq(df2)){
  df2[[i]] <- expand.grid(
    ID = df$ID[i], 
    Group=df$Group[i], 
    Score_per_hit = as.numeric(
      strsplit(as.character(df$Score_per_hit[i]), "/", fixed = TRUE)[[1]])
  )
}
df2 <- do.call("rbind", df2)
df2