如何在R中组合多个.csv文件？ [英] How to combine multiple .csv files in R?

问题描述

我有一个目录包含接近2,000个.csv文件。

I have a directory containing close to 2,000 .csv files.

每个文件具有以下结构（显示500行中的4个）：

Each file has the following structure (showing 4 out of 500 rows):

                       Date;QOF
1    2004-01-04 - 2004-01-10;9
2    2004-01-11 - 2004-01-17;11
3    2004-01-18 - 2004-01-24;13
4    2004-01-25 - 2004-01-31;13

QOF列也是.csv文件的名称，每个文件都有唯一的名称（例如MSTF XQS等）我想从每个.csv文件中的这一列合并到第一个正在读取的.csv文件，它也包含日期变量。换句话说，我想保留第一个文件的所有列，并且只合并所有其他.csv文件的第二列到此文件。最终结果应为：

The column "QOF" is also the name of the .csv file and each file has a unique name (e.g. "MSTF", "XQS" etc.) I would like this column from each .csv file to be merged on to the first .csv file being read which also contains the date variable. In other words I want to keep all columns from the first file and merge only the second column from all other .csv files on to this file. End result should be something like:

                    Date;QOF;MSTF;XQS
1    2004-01-04 - 2004-01-10;9;10;8
2    2004-01-11 - 2004-01-17;11;11;5
3    2004-01-18 - 2004-01-24;13;31;2
4    2004-01-25 - 2004-01-31;13;45;23

到目前为止，我已经尝试过：

So far I have tried this:

filenames <- list.files()

do.call("cbind", lapply(filenames, read.csv, header = TRUE))

推荐答案

mybig <- do.call( rbind, lapply( listfiles, function(nam){ 
                       cbind(name=nam, read.file(paste0(nam,".csv"), header=TRUE) )
                                                }
        )              )

未测试。并注意到我故意不遵循你建议的结构。我不能thnk一个更混乱的数据结构下来工作。您可能正在考虑将此格式用于输出，并且首先需要构建一个数据帧，然后将其写入带分号分隔符的文件。

Untested. And notice that I intentionally did not follow the structure you suggested. I cannot thnk of a more confusing data structure to work with down the line. You might be thinking of using that format for output and would first need to build a dataframe and then write it to a file with semi-colon delimiter.

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