LA_R_5_yrs.R

library(RJSONIO)
library(httr)
library(ggplot2)

api_key <- scan("~/.meetup.apikey", character(), quiet = TRUE)
group_id <- 1414043   ## LA R meetup

req_url <- paste0("http://www.meetup.com/2/events?key=", api_key, 
                  "&group_id=",group_id,"&status=past")
events_data <- fromJSON(rawToChar(GET(req_url)$content))$results

d <- do.call("rbind",lapply(events_data, function(x) 
  data.frame(id = x$id, 
             tm = as.Date(format(as.POSIXct(x$time/1000, origin = "1970-01-01"),"%Y-%m-%d")), 
             venue = if(is.null(x$venue)) NA else x$venue$name,
             name = x$name, attend = x$yes_rsvp_count, wait = x$waitlist_count, 
             stringsAsFactors = FALSE)))

d <- subset(d, attend>17)  ## eliminate cross posting
d$venue <- sapply(strsplit(gsub("^ *","",d$venue)," "),`[[`,1)
d$venue <- ifelse(is.na(d$venue),"other",d$venue)

ggplot(d) + geom_line(aes(x = tm, y = attend, ymin = 0), color = "grey70") +
   geom_point(aes(x = tm, y = attend, color = venue), size = 3) + 
   xlab(NULL) + ylab("attending / waiting list") +
   geom_step(aes(x = tm, y = wait), direction = "vh", color = "#cc0000") + 
   ggtitle("5 years of LA R meetups")