Hello,
Considering your amazing efficiency on pandas, numpy, and more, it would seem to make sense for your module to work with even bigger data, such as Audio (for example .mp3 and .wav). This is something that would help a lot considering the nature audio (ie. where one of the lowest and most common sampling rates is still 44,100 samples/sec). For a use case, I would consider vaex.open('Hu

Having the ability to set an external/advertised hostname is great since it provides users a lot of flexibility in network deployments. However, having it a required argument is a pain for the most common scenario, where the scheduler, client and executors talk to each other in the same network (e.g. k8s or docker-compose).

We should make the external hostname optional. If the scheduler receive

Implements {DataFrame,Series}.empty

Describe the bug
Danfojs does not throw correct error when more than one key specified in the merge function

To Reproduce
Steps to reproduce the behavior:

1. Go to 'https://playnotebook.jsdata.org/'
2. load danfojs version 0.2.4 using load_packages
3. run the following code:

let data = [['K0', 'k0', 'A0', 'B0'], ['k0', 'K1', 'A1', 'B1'],
            ['K1', 'K0', 'A

Hi. I couldn't find a mailing list to ask this directly.

According to the book "The New Technical Trader" by Chande & Kroll (1st ed, Wiley, ISBN 9780471597803), on page 95, the CK long stop is calculated by computing a 10 day simple moving average of the ATR, which they name ATR_10, to which we subtract 3*ATR_10 from highest high of the last 10 days. This quantity will be the preliminar

Problem description

When I use the function of concatenating multiple columns, I find that it does not handle null values as expected.

This is the current output

df.concatenate_columns(["cat_1","cat_2","cat_3"],"cat",sep=",")

I'm using black and isort for other projects (see e.g. https://github.com/hyperopt/hyperopt/pull/748/files) and find them quite useful to have more consistent codebase. I think you should drop python3.5 support though, as black is python3.6+. Is this something you would be open to consider?