Question

我想从一个包含空格分隔的文本文件的文件夹中读取文件，然后将它们作为 csv 文件写出到同一文件夹中。

空格分隔的文本文件很烦人，第二行是破折号，每个文件末尾的三行有一些不正确的摘要值（见下文）。这些已通过“read_fwf”中的“评论”和“跳过”参数删除。如果有更好的方法来实现这一点，请指教。

    Frame   Clusters   Total Area
    -----------------------------
        0          2          353   
        1          2          233   
        2          1           18   
        3          1           18 
      ...        ...         ... 
     6230          1           38   
     6231          2          183   

    Total qualifying frame count = 6105
    Total file cluster count     = 42005
    Total file biomass area      = 8867980

我正在尝试使用 lapply 等 tidyverse 选项而不是编码循环。

我想我正在阅读文本文件。我的失败似乎出在代码的 write.csv 部分。

作为 R 的新用户，我将不胜感激任何建议或语法链接（即括号、缩进等）。论坛帖子的清晰度提示也会有所帮助。谢谢。

    # Clear all variables
    rm(list = ls())

    # Reference tidyverse
    library(tidyverse)

    # Create variable, "folder" for location of text files
    folder <- "C:/Users/stai669/OneDrive - PNNL/Desktop/CRDC_P/DP/DIDSON snip 
    files/largeDataset/Cluster/Aft/N/"

    # Create variable, "file_list" that lists all files in folder for "lapply" to loop through
    filelist <- list.files(path = folder, pattern = "*.txt")

    # Read in each file with "lapply"; other arguments for column names, etc.
    data <- lapply(filelist, function(x) {
                      textfile <- read_fwf(
                      paste(folder, x, sep = ""),
                      fwf_positions(start = c(1, 6, 17), end = c(5, 16, 29),
                      comment = "T",
                      col_names = c("fram", "clust", "biom"),
                      skip = 2,
                      cols(fram = col_integer(), clust = col_integer(), biom =    col_integer())
                      )
    # Write the files to csv in the same folder                          
        write.csv(textfile, file = sub(pattern = "\\.txt$", replacement = ".csv", x = x))
        })

Answer 1

# Clear all variables
rm(list = ls())

# Reference tidyverse
library(tidyverse)

# Create variable, "file_list" that lists all files in folder for "lapply()" to loop through
filelist <- list.files(pattern = "*.txt")

# Read in each file with "lapply"; other arguments for column names, etc.
data <- lapply(filelist, function(x) {
                          textfile <- read_fwf(
                          paste(x, sep = ""),
                          fwf_positions(start = c(1, 6, 17), end = c(5, 16, 29), col_names = c("fram", "clust", "biom")),
                          comment = "T",
                          skip = 2,
                          cols(fram = col_integer(), clust = col_integer(), biom = col_integer())
                          )
# Write the files as csv to the same folder                          
            write.csv(textfile, file = sub(pattern = "\\.txt$", replacement = ".csv", x = x))
})

再次注意，“col_names”参数与“fwf_positions”一起使用。

R: read_fwf () 从文件夹中读取多个文本文件，然后将 csv 文件写入同一文件夹（即，将文本文件文件夹转换为 csv 文件文件夹）

1 个答案: