Iowa code

library(rvest)
library(magrittr)

tmp <- read_html("https://results.thecaucuses.org/")
full <- tmp %>% html_nodes("ul.thead") %>% html_nodes("li") %>% html_text()
sub <- tmp %>% html_nodes("ul.sub-head") %>% html_nodes("li") %>% html_text()
full <- full[-1:-2]
sub <- sub[-1:-2]

counties <- tmp %>%  html_nodes('div.precinct-rows') 
out <- NULL
for(ii in 1:length(counties)){
  count_tmp <- counties[ii] %>%  html_nodes('div.precinct-county') %>%
    html_text()
  
  prec <- counties[ii] %>% html_nodes('div.precinct-data') %>%
    html_nodes('ul')
  tmp_out <- NULL
  for(jj in 1:(length(prec)-1)){
    tmp_out <- rbind(tmp_out, prec[jj] %>% html_nodes('li') %>% html_text())
  }
  
  tmp_trans <- rbind(tmp_out[,2:4], tmp_out[,5:7],
        tmp_out[,8:10], tmp_out[,11:13], 
        tmp_out[,14:16], tmp_out[,17:19],
        tmp_out[,20:22], tmp_out[,23:25],
        tmp_out[,26:28], tmp_out[,29:31],
        tmp_out[,32:34], tmp_out[,35:37],
        tmp_out[,38:40], tmp_out[,41:43])
  tmp_trans <- as.data.frame(apply(tmp_trans, 2, as.numeric))
  tmp_trans$prec <- rep(tmp_out[,1], times=14)
  
  tmp_trans$cand <- c(sapply(full[full!=""], rep, times=nrow(tmp_out)))
  tmp_trans$county <- count_tmp
  
  out <- rbind(out, tmp_trans)
}


names(out)[1:3] <-c('First', 'Final', 'SDE')
ggplot(out[!out$cand %in% c('Bennet', 'Bloomberg', 'Delaney',
                           'Gabbard', 'Other', 'Patrick', 'Steyer'),],
       aes(x=Final-First, y=First)) + geom_point() + 
  facet_wrap(~cand) + theme_minimal()
out$Change <- out$Final - out$First

tmp <- reshape2::dcast(out, county+prec~cand, value.var='Change')

library(GGally)
my_bin <- function(data, mapping, ..., low = "gray", high = "orangered2") {
  ggplot(data = data, mapping = mapping) +
    geom_bin2d(..., bins=20) +
    scale_fill_gradient(low = low, high = high) +
    geom_hline(yintercept = 0, linetype='dashed') +
    geom_vline(xintercept = 0, linetype='dashed') 
}
p <- ggpairs(tmp[,c("Biden", "Buttigieg", "Klobuchar", 
               "Sanders", "Warren", "Yang", "Uncommitted")], 
             diag = list(continuous='barDiag'), 
             lower=list(continuous=my_bin))
p + theme_minimal()  + 
  ggtitle('Change in Candidate Support in Each Precinct')