Longest spell of increasing vote share in national elections

longest_spell.R

library(tidyverse)

longest_increase <- function(sign_d) {
 rles <- rle(sign_d)
 rle_values <- rles$value
 rle_lengths <- rles$length
 rle_lengths <- rle_lengths[which(rle_values == 1)]
 rle_values <- rle_values[which(rle_values == 1)]
 max(rle_lengths)
}

elex <- read.csv("view_election.csv")
elex <- elex %>% 
    filter(election_type == "parliament") %>% 
	mutate(election_date = as.Date(election_date))

foo <- elex %>% 
	dplyr::select(party_id, party_name_english, 
	country_name_short, election_date, vote_share) %>% 
	group_by(country_name_short, party_id, party_name_english) %>% 
	arrange(election_date) %>% 
	mutate(delta = c(NA, diff(vote_share)), 
		sign_d = sign(delta)) %>% 
	summarize(longest_spell = longest_increase(sign_d))

foo %>% 
arrange(desc(longest_spell))