# How to replace scalars with vectors in simple models, such as classification of sentences where 1-hot encoding is replaced with word vectors

I have a problem, which seems simple enough, but I don't know how it is solved in the industry. This has to do with the machinery of feeding data to a model, rather than trying to figure out the best sentence classification model.

Say I have a bunch of sentences and I want to classify them:

...
question: Do you like green eggs and ham?
question: Would you like them in a house?
question: Would you like them with a mouse?
answer: I do not like green eggs and ham.
answer: I would not like them here or there.
answer: I would not like them anywhere.
...


The labels are binary, 'question' and 'answer'. I have to figure out how to train this model.

One way is to use one-hot encoding. Take the whole corpus, sort it, use its index to to mark 0 or 1 if that word appears in the training observation, 0 if it doesn't. So the input becomes a simple matrix of numbers:

X:

0, 0, 0, 1, 0, 0, 1, 1
0, 1, 0, 0, 0, 0, 1, 0
1, 0, 1, 0, 0, 0, 1, 0
0, 1, 0, 0, 0, 0, 0, 0
...


(note that each row above is one-hot-encoding, so each 'cell' represents the presence or absence of a word in a training sample)

Naturally, the corresponding label vector will have two values: 1,0,0,1,1,...

So far, things are pretty straight forward in this silly example.

What if I decided to use word vectors instead? Now a single number (1 or 0) can't represent the presence or absence of a cell in an observation!

As far as I know, sklearn expects a matrix of numbers. Each 'cell' in the example above is now represented by a vector, not a scalar! How do I feed this to my model?

Further, outside of NLP this also applies. For example, in a straight forward business style dataset, it is normal to convert categorical variables to one-hot-encoding. However, what if I decided to use entity embeddings, which are becoming popular. How do I stuff vectors representing scalar values here as well?

I hope my question is clear. Please let me know if it isn't.