How to add N bases to PyRange object (i.e., shifting PyRanges coordinates)

Question

I would like to add n (e.g., 1k) bases to a PyRange object (i.e., shifting PyRanges coordinates). How can I do that?

Input:

import pyranges as pr
gr = pr.random(3)

# gr:
# +--------------+-----------+-----------+--------------+
# | Chromosome   |     Start |       End | Strand       |
# | (category)   |   (int32) |   (int32) | (category)   |
# |--------------+-----------+-----------+--------------|
# | chr1         |  10000000 |  20000000 | -            |
# | chr2         |  20000000 |  30000000 | +            |
# | chr22        |  30000000 |  40000000 | -            |
# +--------------+-----------+-----------+--------------+

Desired output:

# magical command[gr + 1000]:
# +--------------+-----------+-----------+--------------+
# | Chromosome   |     Start |       End | Strand       |
# | (category)   |   (int32) |   (int32) | (category)   |
# |--------------+-----------+-----------+--------------|
# | chr1         |  10001000 |  20001000 | -            |
# | chr2         |  20001000 |  30001000 | +            |
# | chr22        |  30001000 |  40001000 | -            |
# +--------------+-----------+-----------+--------------+

Answer 1

You can use the .extend() method. Starting with your data above, gr.extend({"3": -10000, "5": 10000}) would generate the following:

+--------------+-----------+-----------+--------------+
| Chromosome   |     Start |       End | Strand       |
| (category)   |   (int32) |   (int32) | (category)   |
|--------------+-----------+-----------+--------------|
| chr1         |  10010000 |  20010000 | -            |
| chr2         |  19990000 |  29990000 | +            |
| chr22        |  30010000 |  40010000 | -            |
+--------------+-----------+-----------+--------------+

I don't know a way of to apply this "range extension" in a strand specific way (to be able to generate the desired output exactly) but if this is really needed, you should be able to generate 2 gr objects, one for each strand, do the manipulation and bring these together.