R语言ggplot2做柱形图并在指定的位置添加灰色背景

之前的推文介绍了一个链接，https://simplystatistics.org/2019/08/28/you-can-replicate-almost-any-plot-with-ggplot2/

这个里面有5个R语言ggplot2作图的实例，数据代码都有，非常好的学习素材。但是他的代码相对比较长，初学者看起来可能有些吃力。后面争取出推文把代码都拆解一下。今天的推文介绍一下其中的柱形图实现的代码

image.png

先介绍一个小知识点

ggplot2作图X轴默认坐标轴的刻度是朝下的，Y轴默认的刻度是朝左的，如果要改为朝上和朝右，该如何设置。之前也有人问过这个问题

library(ggplot2)
library(ggstar)

ggplot()+
  geom_star(aes(x=1,y=1),
            size=100,
            starshape=16,
            fill="red")+
  theme_bw()+
  theme(axis.ticks.length.x = unit(-1,'cm'),
        plot.margin = unit(c(1,1,2,1),'cm'),
        axis.text.x = element_text(vjust=-20),
        axis.title.x = element_text(vjust=-20),
        axis.ticks.length.y = unit(-1,'cm'),
        axis.text.y = 
          element_text(
            margin = margin(0,1.2,0,0,'cm')
          ))

image.png

这里我们把axis.ticks.length.x = unit(-1,'cm')刻度线的长度调整为负数就可以了，

但是还遇到一个问题是 横坐标的文本和标题可以通过vjust参数上下调节，纵坐标的参数却不能够用hjust的参数左右调节，不知道是什么原因

下面开始重复开头提到的柱形图

首先是数据，用到的是dslabs这个R包

安装直接使用命令install.packages("dslabs")

加载数据集

library(dslabs)
data("nyc_regents_scores")

给数据集增加一列

library(dplyr)

nyc_regents_scores %>% head()

nyc_regents_scores$total <- rowSums(nyc_regents_scores[,-1], na.rm=TRUE)

对数据集过滤

如果score这一列是缺失值就把这行数据删除

nyc_regents_scores %>% 
  filter(!is.na(score)) -> new_df

最基本的柱形图

new_df %>%
  ggplot(aes(score, total)) + 
  geom_bar(stat = "identity", 
           color = "black", 
           fill = "#C4843C") 

image.png

指定位置添加背景

new_df %>%
  ggplot(aes(score, total)) + 
  annotate("rect", xmin = 65, 
           xmax = 99, 
           ymin = 0, 
           ymax = 35000, 
           alpha = .5) +
  geom_bar(stat = "identity", 
           color = "black", 
           fill = "#C4843C") 

image.png

添加文本注释

new_df %>%
  ggplot(aes(score, total)) + 
  annotate("rect", xmin = 65, 
           xmax = 99, 
           ymin = 0, 
           ymax = 35000, 
           alpha = .5) +
  geom_bar(stat = "identity", 
           color = "black", 
           fill = "#C4843C") +
  annotate("text", 
           x = 66, 
           y = 28000, 
           label = "MINIMUM\nREGENTS DIPLOMA\nSCORE IS 65", 
           hjust = 0, 
           size = 3) +
  annotate("text",
           x = 0, 
           y = 12000, 
           label = "2010 Regents scores on\nthe five most common tests",
           hjust = 0, 
           size = 3)

image.png

修改坐标轴刻度和位置

new_df %>%
  ggplot(aes(score, total)) + 
  annotate("rect", xmin = 65, 
           xmax = 99, 
           ymin = 0, 
           ymax = 35000, 
           alpha = .5) +
  geom_bar(stat = "identity", 
           color = "black", 
           fill = "#C4843C") +
  annotate("text", 
           x = 66, 
           y = 28000, 
           label = "MINIMUM\nREGENTS DIPLOMA\nSCORE IS 65", 
           hjust = 0, 
           size = 3) +
  annotate("text",
           x = 0, 
           y = 12000, 
           label = "2010 Regents scores on\nthe five most common tests",
           hjust = 0, 
           size = 3)+
  scale_x_continuous(breaks = seq(5, 95, 5), 
                     limit = c(0,99)) + 
  scale_y_continuous(position = "right") +
  ggtitle("Scraping By") + 
  xlab("") + ylab("Number of tests")

image.png

最后是对主题进行设置

new_df %>%
  ggplot(aes(score, total)) + 
  annotate("rect", xmin = 65, 
           xmax = 99, 
           ymin = 0, 
           ymax = 35000, 
           alpha = .5) +
  geom_bar(stat = "identity", 
           color = "black", 
           fill = "#C4843C") +
  annotate("text", 
           x = 66, 
           y = 28000, 
           label = "MINIMUM\nREGENTS DIPLOMA\nSCORE IS 65", 
           hjust = 0, 
           size = 3) +
  annotate("text",
           x = 0, 
           y = 12000, 
           label = "2010 Regents scores on\nthe five most common tests",
           hjust = 0, 
           size = 3)+
  scale_x_continuous(breaks = seq(5, 95, 5), 
                     limit = c(0,99)) + 
  scale_y_continuous(position = "right") +
  ggtitle("Scraping By") + 
  xlab("") + 
  ylab("Number of tests")+
  theme_minimal() + 
  theme(panel.grid.major.x = element_blank(), 
        panel.grid.minor.x = element_blank(),
        axis.ticks.length = unit(-0.2, "cm"),
        plot.title = element_text(face = "bold"))

image.png

欢迎大家关注我的公众号

小明的数据分析笔记本

小明的数据分析笔记本 公众号 主要分享：1、R语言和python做数据分析和数据可视化的简单小例子；2、园艺植物相关转录组学、基因组学、群体遗传学文献阅读笔记；3、生物信息学入门学习资料及自己的学习笔记！