I have 100+ EEG EDF files. I want to extract the start time and date along with the recording duration into a data frame. Is there any easy way to extract this data? Preferabely in R or Matlab.
I have succesfully extracted the data using:
library(edfReader)
CHdr <- readEdfHeader("E:/data/EDF/Rtest/EEG1 (2).edf")
summary(CHdr)
format (CHdr$startTime, format="%Y-%m-%d %H:%M:%S", usetz = FALSE)
CHdr$recordedPeriod
But doing this for the 100+ EDF files, might get a bit tiresome...
It is difficult to answer without a reproducible example, but i would suggest looping over your files though there may be a more elegant way to functionalize all this into fewer lines with an apply. Provided they are all in the same directory this should be possible with the following:
library(edfReader)
files <- list.files("E:/data/EDF/Rtest/", pattern = "*.edf")
outputs <- list()
for (i in 1:length(files)) {
i_file <- paste0("E:/data/EDF/Rtest/",files[i])
i_CHdr <- readEdfHeader(i_file)
#whatever else you are doing
outputs[[i]] <- output_from_your_code
rm(i_file, i_CHdr) #plus whatever objects your code has
}
#work with outputs list as necessary; dplyr::bind_rows is often helpful
You can use lapply with readEdfHeader to get all the headers in one code line.
First, a working example with the package data sets.
old_dir <- getwd()
libDir <- system.file("extdata", package = 'edfReader')
setwd(libDir)
Get the .edf filenames and read their headers.
fls <- list.files(pattern = '\\.edf')
edf_headers <- lapply(fls, readEdfHeader)
Next, extract the relevant information and rbind it to create a data.frame.
res <- lapply(edf_headers, function(x){
startTime <- x[['startTime']]
startDate <- substr(x[['recordingId']], 11, 21)
recordDuration <- x[['recordDuration']]
data.frame(startTime, startDate, recordDuration)
})
res <- do.call(rbind, res)
res
# startTime startDate recordDuration
#1 2000-01-01 14:15:16 01-JAN-2000 0.1
#2 2009-12-10 12:44:02 10-DEC-2009 1.0
#3 2009-12-10 12:44:02 10-DEC-2009 1.0
Reset the working directory.
setwd(old_dir)
