ggplot2 案例：蝙蝠侠剧中反派出现的集数

这个案例来源于：Holy ifelse() statements Batman! 不过作者的代码比较老了，我重写了爬取代码，另外作者处理数据过程有点错误，所以我最后画的图和作者的不一样。

首先需要从A Visual Guide to All 37 Villains in the Batman TV Series爬取每个反派出现的季数和集数的数据，为了方便大家复现这个案例，我已经把这个网页下载保存成了 visual-guide-all-37-villains-batman-tv-series.html 文件。

library(tidyverse)
library(rvest)
# 为了方便大家之后的运行，我把这个网页下载下来了：
# download.file('http://mentalfloss.com/article/60213/visual-guide-all-37-villains-batman-tv-series',
#               'visual-guide-all-37-villains-batman-tv-series.html')

# 反派的名字
read_html('visual-guide-all-37-villains-batman-tv-series.html') %>% 
  html_nodes(css = "#article-1 > div > div.article-body-section.top-leaderboard-limit > div.article-body-content-container > div.article-body-content > div.article-body > h4") %>% 
  html_text() %>% 
  as_tibble() -> namedf

read_html('visual-guide-all-37-villains-batman-tv-series.html') %>% 
  html_nodes(css = "strong i") %>% 
  html_text() %>% 
  as_tibble() -> seasondf

bind_cols(namedf, seasondf) %>% 
  set_names(c("name", "v2")) %>% 
  mutate(v2 = str_remove_all(v2, "EPISODES "),
         v2 = str_remove_all(v2, "EPISODE ")) %>% 
  separate_rows("v2", sep = "SEASON ") %>% 
  dplyr::filter(v2 != "") %>% 
  separate(v2, into = c("season", "episode"), 
           sep = " \\(") %>% 
  mutate(episode = str_remove_all(episode, ","),
         episode = str_remove_all(episode, "\\)")) %>% 
  tidytext::unnest_tokens(episode, episode, 
                          token = stringr::str_split, 
                          pattern = " ") %>% 
  dplyr::filter(episode != "") %>% 
  mutate(name = str_remove_all(name, "\\d+\\. ")) %>% 
  type_convert() %>% 
  mutate(name = str_replace_all(name, " \\(", "\n\\(")) %>% 
  mutate(to = str_c(season, episode)) %>% 
  rename(from = name) %>% 
  select(-episode) %>% 
  select(to, from, season) -> df
df

然后可以绘制一副网络图展示各个反派出现的集数：

library(ggraph)
library(igraph)
graph <- graph_from_data_frame(as.data.frame(df))
V(graph)$degree <- degree(graph)

n.names <- unique(df$to)

# Fruchterman-Reingold 布局
ggraph(graph, layout = 'fr') +
  geom_edge_link(aes(
    colour = factor(season)
  )) +
  geom_node_point(aes(
    size = ifelse(V(graph)$name %in% n.names, 1, degree)),
    colour = ifelse(V(graph)$name %in% n.names, '#363636', '#ffffff'),
    show.legend = F) +
  geom_node_text(aes(
    label = name),
    color = ifelse(V(graph)$name %in% n.names, 'grey', 'white'),
    size = ifelse(V(graph)$name %in% n.names, 1.75, 2.5),
    repel = T,
    check_overlap = T) +
  scale_edge_color_brewer('Season',
                          palette = 'Dark2') + 
  theme_graph(background = 'grey20',
              text_colour = 'white',
              base_family = cnfont,
              base_size = 10,
              subtitle_size = 10,
              title_size = 22) +
  theme(legend.position = 'bottom') + 
  labs(
    title = '蝙蝠侠中的反派',
    subtitle = '节点表示蝙蝠侠电视剧的1——3季中的37个反派，尾端的数字表示出现的季和集数。',
    caption = '数据来源: A Visual Guide to All 37 Villains in the Batman TV Series | Mental Floss\n<http://mentalfloss.com/article/60213/visual-guide-all-37-villains-batman-tv-series>')

这样就绘制出了这幅炫酷的网络图。