[R] Looping Through List of .csv Files to Work with Subsets of the Data

[Chad Danyluck]

Hello,

I want to subset specific rows of data from 80 .csv files and write those
subsets into new .csv files. The data I want to subset starts on a
different row for each original .csv file. I've created variables that
identify which row the subset should start and end on, but I want to loop
through this process and I am not sure what to do. I've attempted to write
the loop below, albeit, much of it is pseudo code. If anyone can provide me
with some tips I'd appreciate it.

#### This data file is used to create the variables where the subsetting
starts and ends for each participant ####
mig.data <- read.csv("/Users/cdanyluck/Documents/Studies/MIG -
Dissertation/Data & Syntax/mig.data.csv")

# These are the variable names for the start and end of each subset of
relevant data (baseline, audio, and free)
participant.ids <- mig.processed.data$participant.id
participant.baseline.start <- mig.processed.data$baseline.row.start
participant.baseline.end <- mig.processed.data$baseline.row.end
participant.audio.start <- mig.processed.data$audio.meditation.row.start
participant.audio.end <- mig.processed.data$audio.meditation.row.end
participant.free.start <- mig.processed.data$free.meditation.row.start
participant.free.end <- mig.processed.data$free.meditation.row.end

# read into a list the individual files from which to subset the data
participant.files <- list.files("/Users/cdanyluck/Documents/Studies/MIG -
Dissertation/Data & Syntax/MIG_RAW DATA & TXT Files/Plain Text Files")

# loop through each participant
for (i in 1:length(participant.files)) {

    # get baseline rows
    results.baseline <-
participant.files[participant.baseline.start[i]:participant.baseline.end[i],]

    # get audio rows
    results.audio
<- participant.files[participant.audio.start[i]:participant.audio.end[i],]

    # get free rows
    results.free <-
participant.files[participant.free.start[i]:participant.free.end[i],]

    # write out participant relevant data
    write.csv(results.baseline, file="baseline[i].csv")
    write.csv(results.audio, file = "audio[i].csv")
    write.csv(results.free, file = "free[i].csv")

}

-- 
Chad M. Danyluck, MA
PhD Candidate, Psychology
University of Toronto



“There is nothing either good or bad but thinking makes it so.” - William
Shakespeare

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