amcat.add.parents: Add parents to a data frame of codes
In amcat/amcat-r: R bindings for the AmCAT API

New columns are generated for each code, containing their roots / parents If columns is not specified, adds parents to each codebook column

1	amcat.add.parents(conn, codes, fields, columns = NULL, maxdepth = 1)

`conn`	the connection object from `amcat.connect`
`codes`	a data frame of codes, e.g. from `amcat.codingjob.results`
`fields`	the coding field specifications, e.g. from `amcat.codingjob.results`
`columns`	a character vector containing the column names to add parents to
`maxdepth`	how many parent columns to add for each column, e.g. maxdepth=1 gives roots only