CLN/ENH/BLD: Remove need for 2to3 for Python 3. #4384

jtratner · 2013-07-27T20:58:22Z

Many changes to make codebase compatible in 2 and 3. For range, zip, map, etc. tried to favor iterators over needing to use lists.

Changes:

No more 2to3 in setup.py
merges util/compat and util/py3compat into pandas/compat
incorporates useful parts of the six library into compat (+ adds SIX to LICENSES)
defaults to using iterators in both Python 2 and Python 3 for range, zip, map, and filter
Adds lrange, lzip, lmap, and lfilter, which wrap corresponding iterator methods with lists
Improved type checks (where appropriate --> many need to be rigid to work with pandas)
various other utilities to be Py2/3 compatible (iteritems, iterkeys, itervalues, etc.)
deprecates iterkv with a warning (no longer necessary because library no longer uses 2to3)
compatibility wrapper around dateutil for handling unicode when version <= 2.0 + 1.5 dateutil build in Travis

Switches everything to use special iteritems, so can deprecate as discussed in #4372.

This iteritems use "iteritems" method if available and otherwise uses items.

Checklist of packages to run through 2to3 to check:

Other tasks:

alias __bool__ to __nonzero__

cpcloud · 2013-07-27T21:36:12Z

I think GitHub might explode if I click on the files changed tab 💥

cpcloud · 2013-07-27T21:37:00Z

I think filter is also an iterator in Python 3 IIRC

jtratner · 2013-07-27T21:51:06Z

@cpcloud it is...still coming up on my list :P

jtratner · 2013-07-27T21:53:48Z

@cpcloud actually, only used in one place in library and it's used as an iterator anyways. still need to check for itertools changes.

cpcloud · 2013-07-27T21:57:15Z

great. i think i might use filter in eval-3393, i'll check

jtratner · 2013-07-27T22:16:45Z

@cpcloud just put from six.moves import filter at the top of the file and you'll be fine. It just uses itertools.ifilter under the hood, so slap a list on it otherwise. Very simple

cpcloud · 2013-07-27T22:18:11Z

cool thanks! pandas is going to rule the world soon.

cpcloud · 2013-07-27T22:23:00Z

i hope python 3 testing is going to be faster after this .... those 2to3 runs seem like they take FOREVER

jtratner · 2013-07-27T22:25:59Z

@cpcloud I think it makes the entire test suite a little faster...not sure.

cpcloud · 2013-07-27T22:46:16Z

nice looks like travis build times are 3-4 mins faster that is cool

jtratner · 2013-07-27T22:53:16Z

@cpcloud does Cython have any changes for Python 3?

cpcloud · 2013-07-27T22:56:49Z

I believe all of those issues are taken care of during translation from the Cython to C. I don't see why any Cython would need to be changed. Are you getting compilation errors?

jtratner · 2013-07-27T23:29:07Z

@cpcloud guess I can empirically see that that's not true...just gone through so many changes (and I can't get py3 pandas to work on my mac).

jtratner · 2013-07-27T23:36:09Z

@cpcloud I'm getting all these weird stata reader errors. Do you have any ideas on what might be causing them?

cpcloud · 2013-07-28T00:03:16Z

@jtratner can u link me to a build with those errors?

jtratner · 2013-07-28T00:04:52Z

@cpcloud check out the first few errors on here: https://travis-ci.org/jtratner/pandas/jobs/9563671

cpcloud · 2013-07-28T00:27:21Z

have you tried stepping with a debugger?

jtratner · 2013-07-28T00:28:54Z

@cpcloud I've been having trouble getting pandas with Python 3 to install on my mac, which is why I haven't been able to step through.

jtratner · 2013-07-28T00:29:14Z

@cpcloud but eventually I'll figure out how to get it to work

cpcloud · 2013-07-28T00:30:11Z

ah ok... it's weird because i think you actually have to setup.py install it for 2to3 to run which is annoying whenever you make a change...you have to keep doing it

jtratner · 2013-07-28T00:33:34Z

@cpcloud well, the current build has 2to3 disabled, so you don't actually need to do that. I'm trying a separate build with 2to3 enabled to see if it resolves the problem.

cpcloud · 2013-07-28T00:34:47Z

indeed, i hadn't pulled down your PR in my py3.2 venv yet 😄

cpcloud · 2013-07-28T00:35:22Z

anyway my dev version works so just keep at it i think you'll get it ... i would offer to clone my env but i'm not using mac

jtratner · 2013-07-28T00:36:27Z

@cpcloud okay, pretty sure I can figure it out. It doesn't fail with any of the stata errors with 2to3, so that means I just have to apply some of those fixes and it will work :).

cpcloud · 2013-07-28T00:55:07Z

for some reason the path_or_buf.read() calls are not reading anything...

cpcloud · 2013-07-28T00:55:22Z

(in _read_header)

jtratner · 2013-07-28T01:00:19Z

@cpcloud thanks. And I found all the non-stata errors are resolved by 2to3'ing pandas/core.

cpcloud · 2013-07-28T01:14:20Z

ahh so the problem is actually not in _read_header you need to convert the calls to np.where(map(...)) to np.where(list(map())) then you're golden...i just tried it, it works

cpcloud · 2013-07-28T01:14:33Z

that's in the data method

cpcloud · 2013-07-28T01:14:46Z

i love getting to the bottom of things!

cpcloud · 2013-07-30T01:22:07Z

sorry i wrote that on the wrong thread...see the eval thread!

jreback · 2013-07-30T01:39:00Z

@jtratner

rebases all worked (with a little TLC..) except for 1 thing:

FAIL: test_iterkv_deprecation (pandas.tests.test_frame.TestDataFrame)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/mnt/home/jreback/pandas/build/lib.linux-x86_64-3.3/pandas/tests/test_frame.py", line 10316, in test_iterkv_deprecation
    self.mixed_float.iterkv()
  File "/usr/local/lib/python3.3/contextlib.py", line 55, in __exit__
    next(self.gen)
  File "/mnt/home/jreback/pandas/build/lib.linux-x86_64-3.3/pandas/util/testing.py", line 1058, in assert_produces_warning
    % expected_warning.__name__)
AssertionError: Did not see expected warning of class 'DeprecationWarning'.
``
which works when I run only tests/test_frame.py but not all tests...
?

jtratner · 2013-07-30T01:42:39Z

Maybe I put it in as future warning by accident? Or did we lose the
commit/change that added the deprecation?
On Jul 29, 2013 9:39 PM, "jreback" notifications@github.com wrote:

@jtratner https://github.com/jtratner

rebases all worked (with a little TLC..) except for 1 thing:

FAIL: test_iterkv_deprecation (pandas.tests.test_frame.TestDataFrame)

Traceback (most recent call last):
File "/mnt/home/jreback/pandas/build/lib.linux-x86_64-3.3/pandas/tests/test_frame.py", line 10316, in test_iterkv_deprecation
self.mixed_float.iterkv()
File "/usr/local/lib/python3.3/contextlib.py", line 55, in exit
next(self.gen)
File "/mnt/home/jreback/pandas/build/lib.linux-x86_64-3.3/pandas/util/testing.py", line 1058, in assert_produces_warning
% expected_warning.name)
AssertionError: Did not see expected warning of class 'DeprecationWarning'.
``
which works when I run only tests/test_frame.py but not all tests...
?

—
Reply to this email directly or view it on GitHubhttps://github.com//pull/4384#issuecomment-21764382
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jtratner · 2013-07-30T01:51:16Z

@jreback oh didn't see your last line, I have an idea...let me look.

jtratner · 2013-07-30T01:53:47Z

@jreback which branch?

jreback · 2013-07-30T01:54:35Z

msgpack3 (simpler one)

jtratner · 2013-07-30T02:04:37Z

Why does it require pytest?

======================================================================
ERROR: Failure: ImportError (No module named 'pytest')
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/jtratner/.virtualenvs/pandas3/lib/python3.3/site-packages/nose/failure.py", line 38, in runTest
    raise self.exc_val.with_traceback(self.tb)
  File "/Users/jtratner/.virtualenvs/pandas3/lib/python3.3/site-packages/nose/loader.py", line 413, in loadTestsFromName
    addr.filename, addr.module)
  File "/Users/jtratner/.virtualenvs/pandas3/lib/python3.3/site-packages/nose/importer.py", line 47, in importFromPath
    return self.importFromDir(dir_path, fqname)
  File "/Users/jtratner/.virtualenvs/pandas3/lib/python3.3/site-packages/nose/importer.py", line 94, in importFromDir
    mod = load_module(part_fqname, fh, filename, desc)
  File "/Users/jtratner/.virtualenvs/pandas3/lib/python3.3/imp.py", line 160, in load_module
    return load_source(name, filename, file)
  File "/Users/jtratner/.virtualenvs/pandas3/lib/python3.3/imp.py", line 109, in load_source
    return _LoadSourceCompatibility(name, pathname, file).load_module(name)
  File "<frozen importlib._bootstrap>", line 586, in _check_name_wrapper
  File "<frozen importlib._bootstrap>", line 1023, in load_module
  File "<frozen importlib._bootstrap>", line 1004, in load_module
  File "<frozen importlib._bootstrap>", line 562, in module_for_loader_wrapper
  File "<frozen importlib._bootstrap>", line 869, in _load_module
  File "<frozen importlib._bootstrap>", line 313, in _call_with_frames_removed
  File "/Users/jtratner/projects/python/pandas3/pandas/tests/test_msgpack/test_except.py", line 4, in <module>
    from pytest import raises
ImportError: No module named 'pytest'

======================================================================
ERROR: Failure: ImportError (No module named 'pytest')
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/jtratner/.virtualenvs/pandas3/lib/python3.3/site-packages/nose/failure.py", line 38, in runTest
    raise self.exc_val.with_traceback(self.tb)
  File "/Users/jtratner/.virtualenvs/pandas3/lib/python3.3/site-packages/nose/loader.py", line 413, in loadTestsFromName
    addr.filename, addr.module)
  File "/Users/jtratner/.virtualenvs/pandas3/lib/python3.3/site-packages/nose/importer.py", line 47, in importFromPath
    return self.importFromDir(dir_path, fqname)
  File "/Users/jtratner/.virtualenvs/pandas3/lib/python3.3/site-packages/nose/importer.py", line 94, in importFromDir
    mod = load_module(part_fqname, fh, filename, desc)
  File "/Users/jtratner/.virtualenvs/pandas3/lib/python3.3/imp.py", line 160, in load_module
    return load_source(name, filename, file)
  File "/Users/jtratner/.virtualenvs/pandas3/lib/python3.3/imp.py", line 109, in load_source
    return _LoadSourceCompatibility(name, pathname, file).load_module(name)
  File "<frozen importlib._bootstrap>", line 586, in _check_name_wrapper
  File "<frozen importlib._bootstrap>", line 1023, in load_module
  File "<frozen importlib._bootstrap>", line 1004, in load_module
  File "<frozen importlib._bootstrap>", line 562, in module_for_loader_wrapper
  File "<frozen importlib._bootstrap>", line 869, in _load_module
  File "<frozen importlib._bootstrap>", line 313, in _call_with_frames_removed
  File "/Users/jtratner/projects/python/pandas3/pandas/tests/test_msgpack/test_obj.py", line 4, in <module>
    from pytest import raises
ImportError: No module named 'pytest'

======================================================================
ERROR: Failure: ImportError (No module named 'pytest')
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/jtratner/.virtualenvs/pandas3/lib/python3.3/site-packages/nose/failure.py", line 38, in runTest
    raise self.exc_val.with_traceback(self.tb)
  File "/Users/jtratner/.virtualenvs/pandas3/lib/python3.3/site-packages/nose/loader.py", line 413, in loadTestsFromName
    addr.filename, addr.module)
  File "/Users/jtratner/.virtualenvs/pandas3/lib/python3.3/site-packages/nose/importer.py", line 47, in importFromPath
    return self.importFromDir(dir_path, fqname)
  File "/Users/jtratner/.virtualenvs/pandas3/lib/python3.3/site-packages/nose/importer.py", line 94, in importFromDir
    mod = load_module(part_fqname, fh, filename, desc)
  File "/Users/jtratner/.virtualenvs/pandas3/lib/python3.3/imp.py", line 160, in load_module
    return load_source(name, filename, file)
  File "/Users/jtratner/.virtualenvs/pandas3/lib/python3.3/imp.py", line 109, in load_source
    return _LoadSourceCompatibility(name, pathname, file).load_module(name)
  File "<frozen importlib._bootstrap>", line 586, in _check_name_wrapper
  File "<frozen importlib._bootstrap>", line 1023, in load_module
  File "<frozen importlib._bootstrap>", line 1004, in load_module
  File "<frozen importlib._bootstrap>", line 562, in module_for_loader_wrapper
  File "<frozen importlib._bootstrap>", line 869, in _load_module
  File "<frozen importlib._bootstrap>", line 313, in _call_with_frames_removed
  File "/Users/jtratner/projects/python/pandas3/pandas/tests/test_msgpack/test_pack.py", line 6, in <module>
    from pytest import raises, xfail
ImportError: No module named 'pytest'

======================================================================
ERROR: Failure: ImportError (No module named 'pytest')
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/jtratner/.virtualenvs/pandas3/lib/python3.3/site-packages/nose/failure.py", line 38, in runTest
    raise self.exc_val.with_traceback(self.tb)
  File "/Users/jtratner/.virtualenvs/pandas3/lib/python3.3/site-packages/nose/loader.py", line 413, in loadTestsFromName
    addr.filename, addr.module)
  File "/Users/jtratner/.virtualenvs/pandas3/lib/python3.3/site-packages/nose/importer.py", line 47, in importFromPath
    return self.importFromDir(dir_path, fqname)
  File "/Users/jtratner/.virtualenvs/pandas3/lib/python3.3/site-packages/nose/importer.py", line 94, in importFromDir
    mod = load_module(part_fqname, fh, filename, desc)
  File "/Users/jtratner/.virtualenvs/pandas3/lib/python3.3/imp.py", line 160, in load_module
    return load_source(name, filename, file)
  File "/Users/jtratner/.virtualenvs/pandas3/lib/python3.3/imp.py", line 109, in load_source
    return _LoadSourceCompatibility(name, pathname, file).load_module(name)
  File "<frozen importlib._bootstrap>", line 586, in _check_name_wrapper
  File "<frozen importlib._bootstrap>", line 1023, in load_module
  File "<frozen importlib._bootstrap>", line 1004, in load_module
  File "<frozen importlib._bootstrap>", line 562, in module_for_loader_wrapper
  File "<frozen importlib._bootstrap>", line 869, in _load_module
  File "<frozen importlib._bootstrap>", line 313, in _call_with_frames_removed
  File "/Users/jtratner/projects/python/pandas3/pandas/tests/test_msgpack/test_sequnpack.py", line 7, in <module>
    from pytest import raises
ImportError: No module named 'pytest'

======================================================================
FAIL: test_iterkv_deprecation (pandas.tests.test_frame.TestDataFrame)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/jtratner/projects/python/pandas3/pandas/tests/test_frame.py", line 10316, in test_iterkv_deprecation
    self.mixed_float.iterkv()
  File "/usr/local/Cellar/python3/3.3.0/Frameworks/Python.framework/Versions/3.3/lib/python3.3/contextlib.py", line 55, in __exit__
    next(self.gen)
  File "/Users/jtratner/projects/python/pandas3/pandas/util/testing.py", line 1058, in assert_produces_warning
    % expected_warning.__name__)
AssertionError: Did not see expected warning of class 'DeprecationWarning'.

----------------------------------------------------------------------
Ran 3537 tests in 166.243s

jreback · 2013-07-30T02:06:25Z

its there from where when msgpack tests originally created; been meaning to take it out

jtratner · 2013-07-30T02:06:34Z

@jreback easy to put raises-equivalent into util/testing

Also, you should change this line:

    unpacker = Unpacker(six.BytesIO(b'foobar'), read_size=3)

to the BytesIO from pandas.compat

jreback · 2013-07-30T02:10:20Z

what about the rest of them that directly import from six?

jtratner · 2013-07-30T02:12:09Z

hold on, I have a diff for you.

jreback · 2013-07-30T02:15:39Z

I fixed them all....how do I do raw bytes? b'foo' ?

jtratner · 2013-07-30T02:19:13Z

yeah, that's cross-compatible. I just posted a commit on jtratner/msgpack3 that fixes everything. Main thing is you need to pass string encoding in test_seq.py and wrap around chr

jtratner · 2013-07-30T02:19:28Z

(hadn't seen your note before that...)

jtratner · 2013-07-30T02:19:44Z

binarydata = [bytes(chr(i), 'utf-8') for i in range(256)]

jtratner · 2013-07-30T02:24:34Z

nvm, my example doesn't work for that

cpcloud · 2013-07-30T02:58:25Z

actually assert_raises is in nose.tools

jreback · 2013-07-30T02:59:04Z

jreback@d6c8279

look at test_msgpack/test_seq.py

I had to hack a bit, encoding in py3, but passing str in py2...seems to work, but never could figure out why

jtratner · 2013-07-30T03:08:11Z

@jreback well, in Python 3, everything is unicode, whereas in py2 everything is encoded by default, so using bytes requires setting explicit coding. In python 2 bytes is exactly the same as str.

jreback · 2013-07-30T13:02:21Z

@jtratner I resolved that issue with assert_produces_warning....

I was calling iterkv (in the msgpack ).....which was working correctly. I suspect that the warnings filter somehow was not turned back on correctly though in assert_produces_warning....because this happened before the test failure (of the test for calling iterkv)....

IOW I was calling iterkv accidently, which produced a warning (but I think globally warnings are somehow turned off for DeprecationWarning).....

then when it hit the specific test, warnings were still turned off!

weird

jtratner · 2013-07-30T16:12:02Z

warnings are incredibly finicky. I'm -1 on checking for things like
DeprecationWarnings, especially because I think they don't appear in a
standard interpreter.

jreback · 2013-07-30T16:37:58Z

agreed.....I in fact usually when I test something like this I make it raise while I am testing (which in this case would have found the cases where I didn't fix the deprecated routine)....

so

maybe need something that is a sub-class of DeprecationWarning that assert_produces_warning can really 'catch' (but in normal usage just spews a warning)?

just thinking out loud here

cpcloud · 2013-07-30T16:52:33Z

there's no runtime switch to turn on deprecation warnings?

jreback · 2013-08-05T23:57:18Z

http://ondrejcertik.blogspot.com/2013/08/how-to-support-both-python-2-and-3.html?m=1

I guess we had an easier time than SymPy

jtratner · 2013-08-06T00:07:11Z

python-modernize was an amazingly helpful tool in this - it wraps 2to3 in some useful ways. Running it once gets you 90% of the way there. The big issue for me was that I wanted to use iterators as much as possible so 2.X wouldn't have unnecessary list calls - that took the majority of the time (as well as integrating the six library). I don't know whether it had a performance boost, but if I hadn't cared about that, it probably would've been easier.

There were two particularly hard parts:

Cross-compatible urllib/httplib imports and exceptions.
That weird unicode error we found and fixed with StringIO.

jtratner deleted the better-python3-compat branch July 30, 2013 01:53

This was referenced Aug 6, 2013

2to3 refactor broke test_perf.py #4474

Closed

2to3 refactor broke vbenches #4477

Closed

jreback mentioned this pull request Aug 15, 2013

0.6.0 Roadmap statsmodels/statsmodels#1019

Closed

argriffing mentioned this pull request Jan 6, 2015

For Python2+Python3 compatibility, add some from __future__ imports. cvxpy/cvxpy#164

Closed

CLN/ENH/BLD: Remove need for 2to3 for Python 3. #4384

CLN/ENH/BLD: Remove need for 2to3 for Python 3. #4384

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jtratner commented Jul 30, 2013

FAIL: test_iterkv_deprecation (pandas.tests.test_frame.TestDataFrame)

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