| msg233470 - (view) |
Author: Jon Dufresne (jdufresne) * |
Date: 2015-01-05 17:31 |
| The csv.writer.writerow() does not accept a generator as input. I find this counter-intuitive and against the spirit of similar APIs. If the generator is coerced to a list, everything works as expected. See the following test script which fails on the line "w.writerow(g)". In my opinion, this line should work identically to the line "w.writerow(list(g))". --- import csv f = open('foo.csv', 'w') w = csv.writer(f) g = (i for i in ['a', 'b', 'c']) w.writerow(list(g)) g = (i for i in ['a', 'b', 'c']) w.writerow(g) --- |
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| msg233475 - (view) |
Author: R. David Murray (r.david.murray) *  |
Date: 2015-01-05 18:30 |
| This seems like a sensible enhancement request to me. It is possible it could even be considered a bug, the docs aren't exactly clear on what 'row' is expected to be. |
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| msg233501 - (view) |
Author: Jon Dufresne (jdufresne) * |
Date: 2015-01-06 03:39 |
| I have created an initial patch such that writerow() now allows generators. I have also added a unit test to demonstrate the fix. The code now coerces iterators (and generators) to a list, then operates on the result. I would have preferred to simply iterate over the argument, however, there is a special case where the length of the argument is exactly 1. So coercing to a list makes checking the length simpler. All feedback welcome. |
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| msg233508 - (view) |
Author: R. David Murray (r.david.murray) * |
Date: 2015-01-06 08:26 |
| Hmm. That could be an issue. If someone passes a generator they will generally expect it to be consumed as a generator, not turned into a list implicitly. So it may be better to turn this into a doc bug and require the explicit "list" call :(. |
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| msg233509 - (view) |
Author: Serhiy Storchaka (serhiy.storchaka) * |
Date: 2015-01-06 08:57 |
| The docs mention that "row" should be a sequence, so there is no a bug. Here is a patch which makes writerow() accept an iterable without converting it to a list. It also adds tests for few corner cases and fixes the docs. |
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| msg239192 - (view) |
Author: Martin Panter (martin.panter) * |
Date: 2015-03-24 22:27 |
| Left a question about handling of the unquoted empty field exception on Rietveld. |
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| msg239570 - (view) |
Author: Roundup Robot (python-dev)  |
Date: 2015-03-30 06:22 |
| New changeset cf5b62036445 by Serhiy Storchaka in branch 'default': Issue #23171: csv.Writer.writerow() now supports arbitrary iterables. https://hg.python.org/cpython/rev/cf5b62036445 |
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| msg244689 - (view) |
Author: R. David Murray (r.david.murray) * |
Date: 2015-06-02 19:41 |
| Looks like Serhiy forgot to close this, so closing it. |
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| msg244690 - (view) |
Author: R. David Murray (r.david.murray) * |
Date: 2015-06-02 19:45 |
| No, I just had a stale tab :( :( |
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