Item1,Item2,Item3,Item4
milk,bread,butter,
milk,bread,,
bread,butter,,
milk,butter,eggs,
milk,bread,butter,eggs
bread,eggs,,
milk,bread,butter,
beer,chips,,
beer,chips,salsa,
chips,salsa,,
beer,chips,,
milk,bread,eggs,
milk,diapers,beer,chips
diapers,beer,,
milk,bread,butter,eggs
beer,chips,salsa,
milk,bread,,
bread,butter,eggs,
milk,butter,,
beer,diapers,chips,