how to index a column matrix based on other column matrix?

Hi! I have two column matrix of different lenght (B is little than A). i want to indexing B using values from A and create a new column matrix C with the selected values.

I attached my matrices.

Thanks in advance!

[JESUS DAVID ARIZA ROYETH]

How do you want to index them? What would be the logical procedure?

[Stephen23]

Hopefully those are not timesamps stored as integers!

It is not clear what you mean by indexing, given that the values are on the order of 1e7 - 1e8 and yet the arrays have only hundred or so elements. Perhaps you really mean some set operation e.g. setdiff or to find the indices of matching/non-matching values?

[Ajay Pattassery]

I have inspected your vectors. Could you explain how the new column matrix C is created.