Neighbouring each labels

I am working with influxdb to store my data. I have a column with 0s, 1s and -1s. There's at least 99% of 0s and the remaining with 1s and -1s. I want a freelancer that can neighbouring the 1s and -1s with other 1s and -1s with a python function. An instance of that as input can be ..., 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, ... and output 0, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, 0. As there are about 90 million lines in that database, you will have to consider pooling. Don't worry about that part because I will be able to guide you with another similar script.