Converts a InternalRow to another Row given a sequence of expression that define each
column of the new row. If the schema of the input row is specified, then the given expression
will be bound to that schema.
In contrast to a normal projection, a MutableProjection reuses the same underlying row object
each time an input row is added. This significantly reduces the cost of calculating the
projection, but means that it is not safe to hold on to a reference to a InternalRow after
next() has been called on the Iterator that produced it. Instead, the user must call
InternalRow.copy() and hold on to the returned InternalRow before calling next().
Converts a InternalRow to another Row given a sequence of expression that define each column of the new row. If the schema of the input row is specified, then the given expression will be bound to that schema.
In contrast to a normal projection, a MutableProjection reuses the same underlying row object each time an input row is added. This significantly reduces the cost of calculating the projection, but means that it is not safe to hold on to a reference to a InternalRow after
next()has been called on the Iterator that produced it. Instead, the user must callInternalRow.copy()and hold on to the returned InternalRow before callingnext().