Regex patter to search. Most normal search terms will work fine, too.
ignore.case
Ignore case in search (uses grepl).
fixed
Passed to grepl to match string as-is instead of using regex. See ?grepl.
pluscols
choose columns to return in addition to those where matches are found. Can be a name, number or 'all' to bring back all columns.
exact
Find exact matches intead of pattern matching.
trim
Use trimws to trim columns before exact matching.
spln
Sample data use easyr::spl() before searching. This will speed up searching in large datasets when you only need to identify columns, not all data that matches. See ?spl n argument for more info.