please add support for importing xz-compressed csv-files

[molobrakos]

please add support for importing/opening xz-compressed csv-files, foobar.csv.xz
currently only gzip and bzip2 are supported in backends/csv.py

[cpcloud]

It looks like this is doable for Python >= 2.7

http://stackoverflow.com/a/17217564/564538

@molobrakos i'd happily review a PR for this!

[cpcloud]

one problem that you'll likely run into is that i don't think pandas supports reading xz compressed files. since we depend heavily on pandas for our CSV functionality, it would need to go there first before we could implement it here

[groutr]

For Python 2.7, this looks like a nice library.
http://www.joachim-bauch.de/projects/pylzma/
The lzma library in the stackoverflow post hasn't been maintained/updated in over 5 years.

[cpcloud]

@groutr thanks for looking into that!

FYI.. python3.3+ supports lzma in the standard libraries. Should we support lzma (7z, xz) for versions >= 3.3? And not for python 2.7, or is this considered taboo?

[cpcloud]

I don't think it's that taboo. It'd have to have a solid error message for Python 2 users and there are some issues around the CSV parser, but it could be a nice issue to dig into some of the details of odo

Let us know if you need help

[cpcloud]

One issue is that since pandas doesn't support this kind of compression directly, you'll have to always pass a file like object to read_csv when compression='xz'

Sure. This looks like a nice issue for me to work on.