danceability,energy,key,loudness,mode,speechiness,acousticness,instrumentalness,liveness,valence,tempo,uri,duration_ms,time_signature,artist,song,this_week,last_week,peak_position,weeks_on_chart,date
are columns.
Columns up to signature are only filled for songs that have been on rank 1 at some point.
See https://developer.spotify.com/documentation/web-api/reference/get-audio-features for explanation of audio features.
See https://github.com/mhollingshead/billboard-hot-100 for explanation of billboard data
One row is one song position in charts (weekly), therefore songs can appear multiple times.