Jibran Khan Jibran Khan - 2 months ago 6
R Question

Split up data in CSV file and writing to a file in slices using R

I have a data in CSV file containing 956,678 rows. The following piece of code reads the file and splits the data in groups (each group having 65,000 rows and remainder rows go to last group) in R.

my_file <- read.csv("~myfile_path/file.csv")
grps <- (split(my_file, (seq(nrow(my_file))-1) %/% 65000))
for (i in grps)
{
write.csv(grps, paste("path/output_file", i, ".csv", sep=""))
}


Now, I would like to write these groups as CSV files to the disk. Can anyone suggest me how to do that?

EDIT1:

Based on the comments, I have modified the code and getting the following error:

Error in data.frame(`0` = list(nih_addr_id = c(664L, 665L, 666L, 667L, :
arguments imply differing number of rows: 65000, 46677

Answer

Your write.csv in the loop is trying to write the list as a .csv file, rather than the dataframe element of the list.

Try:

my_file <- read.csv("~myfile_path/file.csv")
grps <- (split(my_file, (seq(nrow(my_file))-1) %/% 65000))
for (i in seq_along(grps)) {
    write.csv(grps[[i]], paste0("path/output_file", i, ".csv"))
}
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