原文链接：http://tecdat.cn/?p=5124
包含术语“生物信息学”的推文示例
第1步：加载所需的软件包
代码语言：javascript复制
# 加载包
library(twitteR)
library(igraph)
library(stringr)第2步：收集关于“生物信息学”的推文
代码语言：javascript复制
# tweets
dm_tweets = searchTwitter("bioinformatics", n=500,)
#获取推文
dm_txt = sapply(dm_tweets, function(x) x$getText())第3步：识别转发
代码语言：javascript复制
# 正则表达式获取推文
grep("(RT|via)((?:\b\W*@\w ) )", dm_tweets,
ignore.case=TRUE, value=TRUE)
rt_patterns = grep("(RT|via)((?:\b\W*@\w ) )",
dm_txt, ignore.case=TRUE)
dm_txt[rt_patterns]
第4步：收集谁转发和谁发布
我们将使用这些结果来形成边缘列表以创建图形
代码语言：javascript复制
# 创建列表存储信息
who_retweet = as.list(1:length(rt_patterns))
who_post = as.list(1:length(rt_patterns))
# 循环
for (i in 1:length(rt_patterns))
{
# 获取推文和转发
twit = dm_tweets[[rt_patterns[i]]]
poster = str_extract_all(twit$getText(),
"(RT|via)((?:\b\W*@\w ) )")
#删除 ':'
poster = gsub(":", "", unlist(poster))
who_post[[i]] = gsub("(RT @|via @)", "", poster, ignore.case=TRUE)
# 转发用户
who_retweet[[i]] = rep(twit$getScreenName(), length(poster))
}
# unlist
who_post = unlist(who_post)
who_retweet = unlist(who_retweet)
第5步：从编辑清单创建图形
代码语言：javascript复制
# 边
retweeter_poster = cbind(who_retweet, who_post)
# 绘制图像
rt_graph = graph.edgelist(retweeter_poster)
# 得到点的名称
ver_labs = get.vertex.attribute(rt_graph, "name", index=V(rt_graph))
第6步：让我们绘制图
代码语言：javascript复制
# 绘图布局
glay = layout.fruchterman.reingold(rt_graph)
# 绘制
par(bg="gray15", mar=c(1,1,1,1))
plot(rt_graph, layout=glay,
vertex.color="gray25",
vertex.size=10,
vertex.label=ver_labs,
vertex.label.family="sans",
vertex.shape="none",
vertex.label.color=hsv(h=0, s=0, v=.95, alpha=0.5),
vertex.label.cex=0.85,
edge.arrow.size=0.8,
edge.arrow.width=0.5,
edge.width=3,
edge.color=hsv(h=.95, s=1, v=.7, alpha=0.5))
# 添加标题
title("nTweets with 'bioinformatics': Who retweets whom",
cex.main=1, col.main="gray95")
第7步：让我们试着给它一个更生物信息学的外观
代码语言：javascript复制
#
par(bg="gray15", mar=c(1,1,1,1))
plot(rt_graph, layout=glay,
vertex.color=hsv(h=.35, s=1, v=.7, alpha=0.1),
vertex.frame.color=hsv(h=.35, s=1, v=.7, alpha=0.1),
vertex.size=5,
vertex.label=ver_labs,
vertex.label.family="mono",
vertex.label.color=hsv(h=0, s=0, v=.95, alpha=0.5),
vertex.label.cex=0.85,
edge.arrow.size=0.8,
edge.arrow.width=0.5,
edge.width=3,
edge.color=hsv(h=.35, s=1, v=.7, alpha=0.4))
# 添加标题
title("nTweets with 'bioinformatics': Who retweets whom",
cex.main=1, col.main="gray95", family="mono")
