CODEWITHSUNDEEP
rlist
user2113499
user2113499

Reputation: 1011

removing rows from dataframes in a list using R

I have several files in one folder that I read into R as a list. Each element in the list is a data frame and I need to remove a random consecutive 6000 rows form each data frame. I can unlist the data frames and pull out the rows but ideally I would like to keep it in the list and just go through each element of the list and remove the rows I need. I thought a for loop or apply function would work but the individual elements don't seem t be recognized as data frames when they're in the list.

Here is what I have so far

files  <- list.files('file location')
fs <- lapply(files, read.table, sep=',',skip=3,header=TRUE)

##separates the list into individual data frames
for (i in seq(fs))
  assign(paste("df", i, sep = ""), fs[[i]])

##selects a random 6000 rows to remove from a dataframe
n <- nrow(df1)
samp <- sample(1:(n-6000),1)
rmvd <- df1[-seq(from = samp, to =samp+5999),]

I would either like to apply the last part to each dataframe individually and put those back into a list or be able to apply it to the list. I want it in a list in the end because it will be easier to write each dataframe to its own csv file.

Upvotes: 1

Views: 1330

Answers (1)

Frank
Frank

Reputation: 66819

If you stick with the list of data.frames, fs, instead of assigning them, you can do something like

lapply(fs, function(x) x[-(sample(nrow(x)-6000,1)+0:5999), ])

If n=nrow(x) is ever under 6000, you're in trouble, of course.

Upvotes: 3

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