FindVars: Find numeric index and names of columns based on patterns
Description
Function ColSeeker extends this by adding class-checks.
FindVars looks up colnames (by default for data-frame rawdata)
based on parts of names, using regular expressions. Be warned that
special characters as e.g. [( need to be escaped or replaced by .
Exclusion rules may be specified as well.
New function ColSeeker() extends this by adding class-checks.