作者：小橙子

来源：小橙子学数据分析

今天要给大家介绍的是cowplot包(作者：Claus O. Wilke)，针对ggplot2的功能扩展包。能把多个ggplot2的图，组合起来

比如利用cowplot包，把"mpg"的车辆信息，根据"整体"与"drv"，按照"总-分"的逻辑，显示在同一张图中：

1library（ggplot2）2library(cowplot) #奶牛画图包3library(ggthemes) #ggplot中的主题包，囊括了很多经典图表形式，比如经济学人、538、华尔街等等45p <-  ggplot(mpg, aes(x = cty, y = hwy, colour = factor(cyl)))+geom_point() + theme_economist() #利用了经济学人的主题6q <-  ggplot(mpg, aes(x = cty, y = hwy, colour = factor(cyl)))+geom_point() + facet_grid(drv ~ .) + theme_economist()78plot_grid(p, q,labels= c('A', 'B'), label_size = 12,label_colour = ("blue"))  2library(cowplot) #奶牛画图包3library(ggthemes) #ggplot中的主题包，囊括了很多经典图表形式，比如经济学人、538、华尔街等等45p <-  ggplot(mpg, aes(x = cty, y = hwy, colour = factor(cyl)))+geom_point() + theme_economist() #利用了经济学人的主题6q <-  ggplot(mpg, aes(x = cty, y = hwy, colour = factor(cyl)))+geom_point() + facet_grid(drv ~ .) + theme_economist()78plot_grid(p, q,labels= c('A', 'B'), label_size = 12,label_colour = ("blue"))  

组合的形式，同时也支持"纵向"排列

1plot_grid(p, q,labels= c('A', 'B'), label_size = 12,label_colour = ("blue"),  align = "v",ncol = 1)'A', 'B'), label_size = 12,label_colour = ("blue"),  align = "v",ncol = 1)

同时也支持"3个图"的组合形式

 1library(ggplot2) 2library(cowplot) 3library(ggthemes) 4 5p <-  ggplot(mpg, aes(x = cty, y = hwy, colour = factor(cyl)))+geom_point() +  6      theme_economist(base_family = "myfonts") 7q <-  ggplot(mpg, aes(x = cty, y = hwy, colour = factor(cyl)))+geom_point() +  8      facet_grid(drv ~ .) + theme_economist(base_family = "myfonts") 9r <-  ggplot(mpg, aes(x = cty) )+geom_bar(fill = "skyblue")+ theme_economist()1011bottom_row <- plot_grid(p, q,labels= c('A', 'B'), label_size = 12,label_colour = ("blue"),  align = "h")12plot_grid(r, bottom_row, labels = c('A', ''), ncol = 1, rel_heights = c(1, 1.2),label_colour = ("blue")) 2library(cowplot) 3library(ggthemes) 4 5p <-  ggplot(mpg, aes(x = cty, y = hwy, colour = factor(cyl)))+geom_point() +  6      theme_economist(base_family = "myfonts") 7q <-  ggplot(mpg, aes(x = cty, y = hwy, colour = factor(cyl)))+geom_point() +  8      facet_grid(drv ~ .) + theme_economist(base_family = "myfonts") 9r <-  ggplot(mpg, aes(x = cty) )+geom_bar(fill = "skyblue")+ theme_economist()1011bottom_row <- plot_grid(p, q,labels= c('A', 'B'), label_size = 12,label_colour = ("blue"),  align = "h")12plot_grid(r, bottom_row, labels = c('A', ''), ncol = 1, rel_heights = c(1, 1.2),label_colour = ("blue"))

同时也支持"子图"的组合形式

1library(viridis) 2ggdraw() +3  draw_plot(p + theme(legend.justification = "bottom"), 0, 0, 1, 1) +4  draw_plot(r + scale_color_viridis(discrete = TRUE) + 5              theme(legend.justification = "top"), 0.5, 0.1, 0.5, 0.4) +6  draw_plot_label(c("A", "B"), c(0, 0.55), c(1, 0.5), size = 15)2ggdraw() +3  draw_plot(p + theme(legend.justification = "bottom"), 0, 0, 1, 1) +4  draw_plot(r + scale_color_viridis(discrete = TRUE) + 5              theme(legend.justification = "top"), 0.5, 0.1, 0.5, 0.4) +6  draw_plot_label(c("A", "B"), c(0, 0.55), c(1, 0.5), size = 15)

cowplot也支持"水印"功能

1ggdraw(r) + 2  draw_plot_label("A", size = 14) + 3  draw_label("小橙子学数据分析", angle = 45, size = 60, alpha = .2)2  draw_plot_label("A", size = 14) + 3  draw_label("小橙子学数据分析", angle = 45, size = 60, alpha = .2)

cowplot也支持"图与背景的重叠"功能

1library(magick)2p <-   ggplot(mpg, aes(x=hwy, group = cyl , fill = factor(cyl) )) + geom_density(alpha = 0.5)3ggdraw() +4  draw_image("https://jeroen.github.io/images/frink.png") +5  draw_plot(p)2p <-   ggplot(mpg, aes(x=hwy, group = cyl , fill = factor(cyl) )) + geom_density(alpha = 0.5)3ggdraw() +4  draw_image("https://jeroen.github.io/images/frink.png") +5  draw_plot(p)

总结

        当需要组合图片的时候，cowplot是个很好的工具。可以实现各种形式的图形组合。

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