Demo code showing how to collect analyze the subreddits a particular user has participated in, using R sintead of python (praw). I don't believe the code is exiting when it should, but this should at least serve as a jumping off point from the person who asked for help: http://www.reddit.com/r/rstats/comments/1tq4au/accessing_the_reddit_api_thro…

scrape_reddit_w_R.r

#install.packages("rjson","RCurl")
library(RCurl)
library(rjson)

get_User_subs_page = function(user, after=NULL, cache=c()){
  
  baseurl = "http://www.reddit.com/user/"
  params = "limit=100"
  if(!is.null(after)){    
    params = paste(params, "&after=",after, sep="")
  }  
  
  userCommentsUrl = paste(baseurl, user, "/.json?",params, sep="")  
  jsonResponse = getURLContent(userCommentsUrl, curl=getCurlHandle())
  StructuredResponse = fromJSON(jsonResponse, unexpected.escape = "keep")  
  
  # Extract subreddits
  n=length(StructuredResponse$data$children) # Count retrieved comment objects
  substemp = rep(NA)
  done = F
  for(i in 1:n){
    obj = StructuredResponse$data$children[[i]]$data
    if(any(cache==obj$id)){
      print("done")
      done=T
      return(list(substemp, NULL, cache, done))
    }
    substemp[i] = obj$subreddit    
    cache=c(cache, obj$id)
  }
  
  nextID = StructuredResponse$data$after # for paging
  list(substemp, nextID, cache, done)
}

USER="ENTER USERNAME HERE"
subreddits = c()
afterID=NULL
ids_cache = c()
done=F
iter=0
while(!done){
  iter=iter+1
  print(iter)
  subs_page = get_User_subs_page(user=USER, after=afterID, cache=ids_cache)  
  subreddits = c(subreddits, subs_page[[1]])
  afterID=subs_page[[2]]
  ids_cache=subs_page[[3]]
  done = subs_page[[4]]
  
  Sys.sleep(2) # sleep 2 seconds to respect reddit API so we don't get blocked
}

aggregate(subreddits, by=list(subreddits), length)