## Vectors and why we need them

We're now moving toward the machine learning part of text analysis - this means that we will now start playing a little less with words and a little more with numbers. Even when we used spaCy, the POS-tagging and NER-tagging, for example, was done through statistical models - but the inner workings were largely hidden for us - we passed over Unicode text and after some magic, we have annotated text.

For Gensim however, we're expected to pass vectors as inputs to the IR algorithms (such as LDA or LSI), largely because what's going on under the hood is mathematical operations involving matrices. This means that we have to represent what was previously a string as a vector - and these kind of representations or models are called **Vector Space Models **[9].

From a mathematical perspective, a vector is a geometric object that has magnitude and direction. We don't need to pay as much attention to this, and rather think of vectors as a way of projecting words onto a mathematical...