R语言之词云图

#任务1
library(RMySQL)

#数据库连接删除函数，每个任务之前最好先清理所有的连接，调用此函数就可以
killDbConnections <- function () {
  all_cons <- dbListConnections(MySQL())
  print(all_cons)
  for(con in all_cons)
    +  dbDisconnect(con)
  print(paste(length(all_cons), " connections killed."))
}
killDbConnections()

#创建数据库连接  
con <- dbConnect(MySQL(),host="localhost",dbname="rdb",user="root",password="")
dbSendQuery(con,'SET NAMES utf8')
rs <- dbSendQuery(con, "SELECT * FROM article WHERE isdone=1")
words = data.frame(word=c(), freq = c())
while (!dbHasCompleted(rs)) {
  chunk <- dbFetch(rs, 10)
  #chunk[,4]为title, #chunk[,5]为abstract
  count=nrow(chunk)
  cnt=1
  while(cnt<=count){
    str = gsub("[[:punct:]]", "", tolower(chunk[cnt,5]))
    str = gsub("聽"," ",str) #在上面的内容中发现这样的特殊字符串，我们替换
    temp = as.vector(unlist(strsplit(str, split = " ")))
    temp_len = length(temp)
    cnt2 = 1
    while(cnt2 <= temp_len){
      if(temp[cnt2] %in% words$word){
        #存在dataframe中
        words[words$word == temp[cnt2],]$freq = words[words$word == temp[cnt2],]$freq+1
      }else{
        #新增
        words = rbind(words,data.frame(word=c(temp[cnt2]),freq=c(1)))
      }
      cnt2 = cnt2+1
    }
    cnt = cnt +1
  }
}
head(words)

Result1：

#任务2
library(wordcloud2)
df=words[0:1000,]
wordcloud2(df)##默认颜色

Result2：

#任务2-1,定制颜色
library(wordcloud2)
df=words[0:1000,]
wordcloud2(df,color=ifelse(df[,2]>2000,'#f02222','#c09292'))

Result2-1：

#任务3
#按照freq的降序排列
new_words =words[order(words$freq,decreasing=T),]
#去掉一些定冠词 of and the
del_word = c('of','the','and','in','to','a','that','is','for','buy','with',
             'we','are','an','this','these','as','from','which','at','their',
             'have','or','our','its','but','how','be','as','here','on','can',
             'into','data','between','both','also','by','yet','than','well',
             'it','not')
words2=words[which(!words$word %in% del_word),]
wordcloud2(words2,shape='star',size=0.5,background='black')