在 for 循环中捕获错误 python

Question

我在 avro 数据 reader 对象上有一个 for 循环

for i in reader:
    print i

然后我在 for 语句中遇到 unicode 解码错误，所以我想忽略该特定记录。所以我这样做了

try:
    for i in reader:
        print i
except:
    pass

但它没有继续下去。我怎样才能克服这个问题

编辑：添加了错误跟踪

    Traceback (most recent call last):
  File "modify.py", line 22, in <module>
    for record in reader:
  File "/usr/lib/python2.6/site-packages/avro-1.7.7-py2.6.egg/avro/datafile.py", line 362, in next
    datum = self.datum_reader.read(self.datum_decoder) 
  File "/usr/lib/python2.6/site-packages/avro-1.7.7-py2.6.egg/avro/io.py", line 445, in read
    return self.read_data(self.writers_schema, self.readers_schema, decoder)
  File "/usr/lib/python2.6/site-packages/avro-1.7.7-py2.6.egg/avro/io.py", line 490, in read_data
    return self.read_record(writers_schema, readers_schema, decoder)
  File "/usr/lib/python2.6/site-packages/avro-1.7.7-py2.6.egg/avro/io.py", line 690, in read_record
    field_val = self.read_data(field.type, readers_field.type, decoder)
  File "/usr/lib/python2.6/site-packages/avro-1.7.7-py2.6.egg/avro/io.py", line 468, in read_data
    return decoder.read_utf8()
  File "/usr/lib/python2.6/site-packages/avro-1.7.7-py2.6.egg/avro/io.py", line 233, in read_utf8
    return unicode(self.read_bytes(), "utf-8")
UnicodeDecodeError: 'utf8' codec can't decode byte 0xb4 in position 14: invalid start byte

会不会是文件损坏了？

编辑2：根据通过 iterobject 的答案中的建议，我修改了代码并得到了这个错误

    Traceback (most recent call last):
  File "modify.py", line 28, in <module>
    print next(iterobject)["filepath"]
  File "/usr/lib/python2.6/site-packages/avro-1.7.7-py2.6.egg/avro/datafile.py", line 362, in next
    datum = self.datum_reader.read(self.datum_decoder) 
  File "/usr/lib/python2.6/site-packages/avro-1.7.7-py2.6.egg/avro/io.py", line 445, in read
    return self.read_data(self.writers_schema, self.readers_schema, decoder)
  File "/usr/lib/python2.6/site-packages/avro-1.7.7-py2.6.egg/avro/io.py", line 490, in read_data
    return self.read_record(writers_schema, readers_schema, decoder)
  File "/usr/lib/python2.6/site-packages/avro-1.7.7-py2.6.egg/avro/io.py", line 690, in read_record
    field_val = self.read_data(field.type, readers_field.type, decoder)
  File "/usr/lib/python2.6/site-packages/avro-1.7.7-py2.6.egg/avro/io.py", line 468, in read_data
    return decoder.read_utf8()
  File "/usr/lib/python2.6/site-packages/avro-1.7.7-py2.6.egg/avro/io.py", line 233, in read_utf8
    return unicode(self.read_bytes(), "utf-8")
  File "/usr/lib/python2.6/site-packages/avro-1.7.7-py2.6.egg/avro/io.py", line 226, in read_bytes
    return self.read(self.read_long())
  File "/usr/lib/python2.6/site-packages/avro-1.7.7-py2.6.egg/avro/io.py", line 184, in read_long
    b = ord(self.read(1))
TypeError: ord() expected a character, but string of length 0 found

Answer 1

你需要循环内的try/except:

    for i in reader:
       try: 
           print i
       except UnicodeEncodeError:
           pass

顺便说一句，最好指定您要捕获的特定错误类型（就像我对 except UnicodeEncodeError: 所做的那样，否则您的代码可能很难调试！

Answer 2

您可以排除 specific error，避免未知错误被忽视。

Python 3.x:

try:
    for i in reader:
        print i
except UnicodeDecodeError as ue:
    print(str(ue))

Python 2.x:

try:
    for i in reader:
        print i
except UnicodeDecodeError, ue:
    print(str(ue))

通过打印错误可以知道发生了什么。当你只使用 except 时，你 except anything（这可能包括一个模糊的 RuntimeError），你永远不知道发生了什么。它有时很有用，但很危险，通常是一种不好的做法。

Answer 3

如果您的错误在 for i in。然后试试这个，如果 UnicodeDecodeError 发生，它将跳过迭代器中的元素。

iterobject = iter(reader)
while iterobject:
    try:
        print(next(iterobject))
    except StopIteration:
        break
    except UnicodeDecodeError:
        pass

在 for 循环中捕获错误 python

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