重构长尝试-除链 [英] Refactor long try-except chain

问题描述

我觉得该序列可能写得更短：

I have a feeling that this sequence might be written shorter:

dim = Dimension.objects.get(pk=rows['pk'])
try:
    dim.name = rows['name']
except KeyError:
    pass
try:
    dim.external_flg = rows['external_flg']
except:
    pass
try:
    dim.ext_owner = rows['ext_owner']
except KeyError:
    pass
try:
    dim.ext_table_name = rows['ext_table_name']
except KeyError:
    pass
try:
    dim.ext_start_date_column_name = rows['ext_start_date_column_name']
except KeyError:
    pass
try:
    dim.ext_end_date_column_name = rows['ext_end_date_column_name']
except KeyError:
    pass

我从未在Python代码优化和处理异常方面有过任何经验，但我很高兴有

I've never had any experience in Python code optimization and working with exceptions but I'd be glad to have an alternative examples how it could be shortened.

谢谢！

推荐答案

我们 dict.get（）方法：

dim.name = rows.get('name', dim.name)

或者，对于更多的DRY解决方案，将所有分配到循环中：

Or, for more DRY solution, put all assignments into the loop:

for field_name in ('name', 'external_flg', 'ext_owner', 'ext_table_name',
                   'ext_start_date_column_name', 'ext_end_date_column_name'):
    if field_name in rows:
        setattr(dim, field_name, rows[field_name])

要处理列表数据，您可以进行类似的循环：

To handle the list data you can make the similar loop:

for i, field_name in enumerate(('name', 'external_flg', 'ext_owner',
                                'ext_table_name', 'ext_start_date_column_name',
                                'ext_end_date_column_name')):
    if i < len[rows]:
        setattr(dim, field_name, rows[i])

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