Duplicate words within a string by variable amount

March 15, 2024

I have a dataframe where one column contains an ID, and the other column contains a series of words with numbers associated with them. As and example:

ColA   ColB
 A     Banana:2;Kiwi:4;Apple:1
 B     Kiwi:1;Orange:4

I would like to duplicate each of the words in ColB by the number associated with it. So, the output I’m looking for would be:

ColA   ColB
 A     Banana;Banana;Kiwi;Kiwi;Kiwi;Kiwi;Apple
 B     Kiwi;Orange;Orange;Orange;Orange

Any suggestions or solutions would be greatly appreciated! Thanks

>Solution :

cbind(df, C = sapply(strsplit(df$ColB, ';'), 
    \(x)paste(do.call(rep, unname(read.table(text=x, sep=':'))), collapse = ';')))

  ColA                    ColB                                       C
1    A Banana:2;Kiwi:4;Apple:1 Banana;Banana;Kiwi;Kiwi;Kiwi;Kiwi;Apple
2    B         Kiwi:1;Orange:4        Kiwi;Orange;Orange;Orange;Orange

df %>%
   separate_longer_delim(ColB, delim = ';')%>%
   separate_wider_delim(ColB, names = c('x','times'), delim = ':')%>%
   uncount(as.numeric(times))%>%
   summarise(ColB = str_c(x, collapse = ';'), .by = ColA)

# A tibble: 2 × 2
  ColA  ColB                                   
  <chr> <chr>                                  
1 A     Banana;Banana;Kiwi;Kiwi;Kiwi;Kiwi;Apple
2 B     Kiwi;Orange;Orange;Orange;Orange

transform(df, ColB = gsubfn::gsubfn("(\\w+):(\\d+)", \(x,y)paste(rep(x,as.numeric(y)), collapse = ";"), ColB))
  ColA                                    ColB
1    A Banana;Banana;Kiwi;Kiwi;Kiwi;Kiwi;Apple
2    B        Kiwi;Orange;Orange;Orange;Orange