used as feature name prefix.
Featurize a single row.
Featurize a single row.
input row.
output indices.
output values.
this interface isn't very Scala-esce, but it avoids lots of allocation. Also due to SparseVector limitations we don't support 64bit indices (e.g. indices are signed 32bit ints)
input field index.
input field index.
Pre-hashed feature index.
bit mask applied to final hash.
pre-hashed namespace.
Featurize string into native VW structure. (hash(column name + value):1)