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Fix #1537721: add writeheader() method to csv.DictWriter.

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Reviewed by skip.montanaro and thomas.wouters.
This commit is contained in:
Dirkjan Ochtman 2010-02-23 21:09:52 +00:00
parent 92bd059c67
commit 8614817875
4 changed files with 20 additions and 0 deletions
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4
Lib/csv.py
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@ -132,6 +132,10 @@ class DictWriter:
self.extrasaction = extrasaction
self.writer = writer(f, dialect, *args, **kwds)
def writeheader(self):
header = dict(zip(self.fieldnames, self.fieldnames))
self.writerow(header)
def _dict_to_list(self, rowdict):
if self.extrasaction == "raise":
wrong_fields = [k for k in rowdict if k not in self.fieldnames]

4
Lib/test/test_csv.py
View file

@ -598,8 +598,12 @@ class TestDictFields(unittest.TestCase):
fileobj = os.fdopen(fd, "w+b")
try:
writer = csv.DictWriter(fileobj, fieldnames = ["f1", "f2", "f3"])
writer.writeheader()
fileobj.seek(0)
self.assertEqual(fileobj.readline(), "f1,f2,f3\r\n")
writer.writerow({"f1": 10, "f3": "abc"})
fileobj.seek(0)
fileobj.readline() # header
self.assertEqual(fileobj.read(), "10,,abc\r\n")
finally:
fileobj.close()