"xifti"Select column indices to keep in a "xifti". Can also be used to
reorder the columns.
select_xifti(xifti, idx, add_meta = "select")A "xifti" object.
The column indices to keep, in order.
Add idx to xifti$meta$cifti$misc[[add_meta]]
for reference. Default: "select". If NULL or an empty string,
do not add a metadata entry.
The "xifti" with only the selected columns.
Other functions for manipulating `xifti` objects:
add_surf(),
apply_xifti(),
combine_xifti(),
convert_to_dlabel(),
merge_xifti(),
newdata_xifti(),
remove_xifti(),
transform_xifti()