复杂的多个csv合并在r

Question

We have two types of dataframes DF_1 and DF_2 each read from csv files with file names of the types

1) DF_1 csv file name of randomNumbers-text1.csv for.

2) DF_2 csv file name of randomNumbers-text2.csv for.

They are perfectly merged into a single dataframe called merged_DF by

merged_DF = merge(DF_1, DF_2)

Now comes the tricky part.

The working directory is made up of around 13000 csv files where half is of the DF_1 csv file name type and the other of the DF_2 csv file type (see point 1 & 2 above).

Problem: How does one perform the above described perfectly merged operation on all approx. 13000 csv files and combine the output into a single combined dataframe call it combined_merged_DF?

How does one solve this the R way

Any help is much appreciated :)

Answer 1

Let's assume the files in the directory are 124-type1.csv , 723-type1.csv , 899-type1.csv , 124-type2.csv , 723-type2.csv , 100-type2.csv , wrong-file.csv . You could do:

csv_files <- list.files("./path/to/csvs", ".csv$")
# [1] "124-type1.csv"  "723-type1.csv"  "899-type1.csv"  "124-type2.csv" 
# [5] "723-type2.csv"  "100-type2.csv"  "wrong-file.csv"

ids_in_common <- intersect(
  sub("-type1\\.csv$", "", grep("type1", csv_files, value = TRUE)),
  sub("-type2\\.csv$", "", grep("type2", csv_files, value = TRUE))
)
# [1] "124" "723"
do.call("rbind", lapply(ids_in_common, function(id) {
  merge(
    read.table(file.path("./path/to/csvs", paste0(id, "-type1.csv"))),
    read.table(file.path("./path/to/csvs", paste0(id, "-type2.csv")))
  )
}))