script.R

library(boot)
library(dplyr)
library(magrittr)
library(purrr)
library(ReporteRs)

# get some data -----
data(melanoma)

melanoma$Status = c( 'Melanoma', 'Alive' , 'Non-melanoma' )[melanoma$status]
melanoma$Gender = ifelse( melanoma$sex > 0, 'Male', 'Female' )
melanoma$Ulceration = ifelse( melanoma$ulcer > 0, 'Present', 'Absent' )

data = melanoma %>% 
  group_by( Status, Ulceration ) %>% 
  summarize( Mean = round( mean( thickness, na.rm = T ), 3 ), 
             SD = round( sd( thickness, na.rm = T ), 3 ), 
             Median = median( thickness, na.rm = T )
  )

data = as.data.frame( data )

# pain to get the data.frame in a correct format -----
list_datas <- split(data, data$Status) %>% map( function(x){
  x[,-1]
})
newdata <- group_by(data, Status) %>% do(head(.,n=1)) %>% ungroup()
list_titles <- split(newdata, newdata$Status)

newdata <- map2_df(list_datas, list_titles, function(x, z) bind_rows(z, x))


# Start creating the table

mytable1 <- vanilla.table(newdata) %>% 
  spanFlexTableColumns(i = which(!is.na(newdata$Status)), from = 1, to = ncol(newdata) ) %>% 
  setFlexTableWidths(widths = c( .7, rep(1,ncol(newdata)-1)))
mytable1[which(!is.na(newdata$Status)),] <- textBold()
mytable1[] <- parCenter(padding=2)
mytable1[, to = "header"] <- parCenter(padding=2)
mytable1[,1] <- parLeft(padding=2)

# print in the viewer 
print( mytable1 )

# print in test.docx
docx() %>% 
  addFlexTable(mytable1) %>% 
  writeDoc(file = "test.docx")