在R中，我如何为多个csv文件制作方框图并导出为pdf文件

Question

我想为80个csv文件制作boxplot，文件名如下：-NY_two.csv、CA_three.csv、FL_three.csv、....、NY_ten.csv。

理想包括

(I( boxplot(导出为pdf，每页2张图(

请参阅下面的80个csv文件中的3个

# All 80 files have the same column names - state, dept, year and revenue
#copy and paste to generate 3 out of 80 csv, 
# The datasets generated below represent 3 out of the 80 csv files
# Dataset 1
state <-c("NY","NY","NY","NY","NY","NY","NY","NY","NY","NY","NY","NY","NY","NY","NY","NY","NY","NY","NY","NY")
dept <- c("energy","energy","energy","energy","works",'works','works','works','fin','fin','fin','fin','parks','parks','parks','parks','trans','trans','trans','trans')
year <- c("two","two","two","two","two","two","two","two","two","two","two","two","two","two","two","two","two","two","two","two")
revenue <-c(1212.9,1253,1244.4,5123.5,1312,3134,515.8,2449.9,3221.6,3132.5,2235.09,2239.01,3235.01,5223.01,4235.6,2204.5,2315.5,6114,4512,3514.2)
NY_two <-data.frame(state,dept,year,revenue)

# Dataset 2
state <- rep("FL",20)
dept <- c("energy","energy","energy","energy","works",'works','works','works','fin','fin','fin','fin','parks','parks','parks','parks','trans','trans','trans','trans')
year <- rep("three",20)
revenue <-c(112.9,123,124,523.5,112,334,55,449,221.6,332,235,239,235,223,235.6,204,315.5,614,512,514.2)
FL_three <- data.frame(state,dept,year,revenue)
# Dataset 3
state <- rep("CA",20)
dept <- c("energy","energy","energy","energy","works",'works','works','works','fin','fin','fin','fin','parks','parks','parks','parks','trans','trans','trans','trans')
year <- rep("three",20)
revenue <-c(1102.9,1023,1024,5203.5,1012,3034,505,4049,2021.6,3032,2035,2039,2035,2023,2035.6,2004,3015.5,6014,5012,5014.2)
CA_three <- data.frame(state,dept,year,revenue)
# exporting the the above datasets as csv files ( imagine them as 3 out of the 80 files)
# set the path in the write.csv(/path/.csv) to collect the datasets
write.csv(NY_two,"C:\Path to export the DataFrame\NY_two.csv", row.names = FALSE)
write.csv(FL_three,"C:\Path to export the DataFrame\FL_three.csv", row.names = FALSE)
write.csv(CA_three,"C:\Path to export the DataFrame\CA_three.csv", row.names = FALSE)

我的尝试

# Desirables include
#(I) plot the boxplot & export as pdf file (2 graphs per page)
######################################################################################
library(ggplot2)
# import all csv files in the folder
files <- list.files("C:\path to the files\", pattern="*.csv", full.names = T)
files
# set the pdf file path, I want two plots per page
pdf(file = "/Users/Desktop/boxplot_anova.pdf")
#specify to save plots in 2x2 grid
par(mfrow = c(2,2))
out <- lapply(1:length(files), function(idx) {
# read the file
this_data <- read.csv(files[idx], header = TRUE) # choose TRUE/FALSE accordingly
# boxplot using ggplot
p <-ggplot(this_data, aes(x = dept, y = revenue, fill = dept)) + 
stat_boxplot(geom = "errorbar", width = 0.15) + geom_boxplot(alpha = 0.8,    # Fill transparency
colour = "#474747",   # Border color
outlier.colour = 1)+ theme(panel.background = element_blank())+ ggtitle("Title using each file name ")
p
dev.off() 
})
out

请提前分享您的代码，thanx

Answer 1

有几个单独的问题可能会导致代码出现问题：

函数中生成绘图的

1. 可能无法正确导出(使用plot(p)或print(p)而不是p(
2. 你必须在循环之前打开pdf设备，然后关闭它，而不是在循环内。例如，这在原则上是可行的：

pdf(file = "boxplot_anova.pdf")
#specify to save plots in 2x2 grid
par(mfrow = c(2,2))
out <- lapply(1:length(files), function(idx) {
# read the file
this_data <- read.csv(files[idx], header = TRUE) # choose TRUE/FALSE accordingly
# boxplot using ggplot
p <-ggplot(this_data, aes(x = dept, y = revenue, fill = dept)) + 
stat_boxplot(geom = "errorbar", width = 0.15) + geom_boxplot(alpha = 0.8,    # Fill transparency
colour = "#474747",   # Border color
outlier.colour = 1)+ theme(panel.background = element_blank())+ ggtitle("Title using each file name ")
plot(p)
})
out
dev.off() 

3. 由于ggplot2不使用基本图形，因此上面的代码不会在同一页上绘制(最多4个，这是您从mfrow(2,2)中期望的(图。例如，使用cowplot包中的plot_grid函数来实现此功能。要生成多个页面，请将绘图列表拆分为匹配数量的元素，例如每页4个绘图：

res <- lapply(files, function(x){
this_data <- read.csv(x, header = TRUE) # choose TRUE/FALSE accordingly
# boxplot using ggplot
ggplot(this_data, aes(x = dept, y = revenue, fill = dept)) + 
stat_boxplot(geom = "errorbar", width = 0.15) + 
geom_boxplot(alpha = 0.8,    # Fill transparency
colour = "#474747",   # Border color
outlier.colour = 1)+ 
theme(panel.background = element_blank()) + 
ggtitle(gsub("(.*/)(.*)(.csv)", "\2", x))
})
# set the pdf file path, I want two plots per page
pdf(file = "boxplot_anova.pdf")
lapply(split(res, ceiling(seq_along(res)/4)), 
function(x) plot_grid(plotlist=x, ncol=2, nrow=2))
dev.off()