Question

我是R的新手，似乎很难创建一个for循环来创建一个包含6个图表（2列x 3行）的PDF图形表。我使用以下循环将CSV导入单独的数据帧。

##create filenames object that lists the csv files in a folder
filenames <-  list.files(path="C:/Survey_Stage/Data_Transfer/Survey_Stage/Stage_Discharge_Relations/CIDA/", pattern="*.csv")

##run loop that imports each csv file in the folder, creates a dataframe, assigns the filename to the dataframe, and adds column names
for(i in filenames)
{
filepath <-file.path("C:/Survey_Stage/Data_Transfer/Survey_Stage/Stage_Discharge_Relations/CIDA/",    paste(i, sep=","))
assign(i, read.table(filepath, header = TRUE, sep = ",")[,c('SP_elev', 'flow')])
}

在我的项目中，我总共有23个csv，并且想要制作6张图形表。

下面是csv导入循环中生成的数据框的示例。

> Z041R.csv
    SP_elev  flow
1  840.5466  5430
2  840.9774  8285
3  841.1020  9162
4  841.2236 10175
5  842.4053 18450
6  840.7600  6780
7  840.9493  8110
8  841.6590 12700
9  842.6615 20200
10 841.2138 10175
11 845.0801 41977
12 841.4786 11431
13 841.6829 13000
14 845.1645 42500
15 841.6142 12400
16 841.2574 10200
17 842.2315 16400
18 840.9390  8040

I flow是自变量，SP_elev是因变量。我已经想出了如何单独创建grahic表，但是真的想要一个for循环来自动化这个过程。有什么想法吗？

这是我试过的循环。

##run loop to plot the csv files 

pdf(file="myplots.pdf",paper="letter")

par(mfrow=c(3,2)) 

for(i in filenames)
{
plot (data.frame(i[flow], i[elevation]), xlab=expression(paste("Discharge (", ft^3, "/s)",sep = "")), ylab= "Elevation (m)", main = i)
}

dev.off()

谢谢，

Dubbdan

Answer 1

我认为你需要这样的东西。假设每个csv文件恰好有2列。否则，从变量“crtdata。

中提取所需的列

pdf(file="myplots.pdf",paper="letter")
for(i in filenames)
{
    crtdata = read.csv(i)
    plot (crtdata, xlab=expression(paste("Discharge (", ft^3, "/s)",sep = "")), ylab= "Elevation (m)", main = i)
}
dev.off()

Answer 2

这只是@BigFinger解决方案的一个小调整（带注释）：

# read in list of filenames
filenames <- list.files(path="C:/Survey_Stage/Data_Transfer/Survey_Stage/Stage_Discharge_Relations/CIDA/", pattern="*.csv")

# open the PDF device
pdf(file="myplots.pdf", paper="letter")

# loop through the filenames
for(i in filenames) {

  # build the path to the current file
  filepath <- file.path("C:/Survey_Stage/Data_Transfer/Survey_Stage/Stage_Discharge_Relations/CIDA", paste(i))

  # read in the data frame
  dat <- read.csv(filepath)

  # plot the chart using column names just incase they aren't all in the same exact format
  plot (dat[,c('SP_elev', 'flow')], xlab=expression(paste("Discharge (", ft^3, "/s)",sep = "")), ylab= "Elevation (m)", main = i)

}

# close the PDF device
dev.off()

如果您不想在地块标题中使用main = gsub(".csv", "", i, fixed=TRUE)，则可以在plot来电中执行.csv。

在R中批量创建图形表

2 个答案: