[R] Draw a wordcloud

# 加载rJava、Rwordseg库
library(rJava);
library(Rwordseg);
library(RColorBrewer);

# == 读入数据
lecture=read.csv("G:\\test.txt",sep=",",header=TRUE,fileEncoding="UTF-8");
# 查看前几行，看是否有字符编码问题
head(lecture);
# 获取数据集长度
n=length(lecture[,1]);
print(n)  

# == 文本预处理
res=lecture[lecture!=" "];
#剔除URL
res=gsub(pattern="http:[a-zA-Z\\/\\.0-9]+","",res);
#剔除特殊词
res=gsub(pattern="[我|你|的|了|是|和|阳|创业|宁阳]","",res);       

# == 分词+频数统计
words=unlist(lapply(X=res, FUN=segmentCN));
word=lapply(X=words, FUN=strsplit, " ");
v=table(unlist(word));
# 降序排序
v=rev(sort(v));
d=data.frame(word=names(v), freq=v);
# 过滤掉1个字和词频小于100的记录
d=subset(d, nchar(as.character(d$word))>1 & d$freq>=10)  

require(wordcloud)
library(RColorBrewer);
dd = head(d, 50)
op = par(bg = "lightyellow")      #背景为亮黄色
rainbowLevels = rainbow((dd$freq)/(max(dd$freq) - 10))      #不知道什么意义，删除后图形无太大变化
text(family = "Kai")
wordcloud(d$word, d$freq, scale=c(5,0.5),  random.order=FALSE, colors=brewer.pal(8, "Dark2"),use.r.layout=FALSE) #
par(op)