Read and load Functional Connectivity matrices or volumes

This function is a helper function to quickly read and import in R functional connectivity matrices stored as standard .csv files or lesion/disconnection data stored as nifti files. Files (.csv) must adhere to a strict format: .csv files with no header nor row names. It is of PARAMOUNT importance that FC matrices/volumes are correctly ordered in their folder, according to participants' IDs (and therefore the behavioral score(s) to predict). Note that characters are ordered alphabetically by default in R, thus you may want to ensure that participants with low IDs (e.g. # 5) are identified by file names preserving this order (e.g. FC 05.csv).

loadFC(
  path = choose.dir(),
  files = NULL,
  quick = c("default", "data.table", "parallel")
)

Arguments

path	Path to the input files. If empty, it prompts the user to select it manually via a selection menu. Only FC matrices or nifti files must be included in the folder. The function performs a cheap guess to understand which input is passed. Files other than those are disregarded.
files	An optional list of file names, e.g. as created by list.files(). If this is supplied, path is overwritten as the file addressed are assumed to be relative.
quick	For csv files: the default uses base R, which may be slow if the FC matrices are too many. Option "data.table" uses data.table::fread(), which is sensibly faster when FC matrices are many; data.table must be installed. Option "parallel" uses future.apply::future_lapply(): future.apply must be installed, your machine should have multiple cores available for use, and threads should be defined explicitly beforehand by the user (e.g. by calling plan(multisession)).

Value

A list of lists including the FC matrices/volumes, stored as data.frames or arrays.