Finds the element in an object for one of the following:
ID
eye
Visual acuity
getElem search a vector, the column names (data frame) or the names (list)
getElem_id(obj, id_chr)getElem_eye(obj, eye_chr)
getElem_va(obj, va_chr)
getElem_iop(obj, iop_chr)
can be vector, data frame or list
strings to identify ID colums.
named list with strings for "r" and "l" names have to be "r" and "l"!
named list with strings for "whole" and "part" names have to be "whole" and "part"!
named list with strings for "whole" and "part" names have to be "whole" and "part"!
vector
Other string matching functions:
recodeye(),
set_codes(),
sort_substr(),
str_func_facs