remove_repeats.R

suppressWarnings({
  suppressPackageStartupMessages({
    library(dplyr)
    library(knitr)
  })
})

remove_repeats= function(x, cols){
  remove_rep= function(df, this_col){
    this_vec= as.character(unlist(df[,this_col]))
    df[,this_col]= unlist(lapply(seq(length(rle(this_vec)$values)), 
                                 function(x) c(rle(this_vec)$values[x], 
                                               rep("", rle(this_vec)$lengths[x]-1))))
    df
  }
  for(c in cols){
    x= remove_rep(x, c)
  }
  x
}


df= as.data.frame(Titanic)  %>%
  arrange(Class, Sex, Age, Survived) %>%
  select(Class, Sex, Age, Survived, Freq)
df= remove_repeats(df, c("Class", "Sex", "Age", "Survived"))

kable(df)

Class	Sex	Age	Survived	Freq
1st	Male	Child	No	0
			Yes	5
		Adult	No	118
			Yes	57
	Female	Child	No	0
			Yes	1
		Adult	No	4
			Yes	140
2nd	Male	Child	No	0
			Yes	11
		Adult	No	154
			Yes	14
	Female	Child	No	0
			Yes	13
		Adult	No	13
			Yes	80
3rd	Male	Child	No	35
			Yes	13
		Adult	No	387
			Yes	75
	Female	Child	No	17
			Yes	14
		Adult	No	89
			Yes	76
Crew	Male	Child	No	0
			Yes	0
		Adult	No	670
			Yes	192
	Female	Child	No	0
			Yes	0
		Adult	No	3
			Yes	20