filters

Define filters for soep dataframes

Functions

age_filter(df, ip)	Add column "sage" to dataframe.
filter_df(df, ip, set_year)
households_filter(df, ip)	Keep the first non NaN row per household for all variables that are not gebjahr, hid or syear.
netto_filter(df)	Limit hh interviews to those that were conducted successfully.
year_filter(df[, set_year])	Select only interview years of certain year.