Pymongo $regexMatch 正则表达式选项中的无效标志：u

Question

使用 PyMongo 3.10.1，MongoDB 4.2 下面的聚合，使用 $group 和 $regexMatch 在命令行上工作正常：

db.accounts.aggregate([
        {'$lookup': {'from': 'users', 'localField': '_id', 'foreignField': 'user_id', 'as': 'users'}},
        {'$unwind': "$users"},
        { "$group": {
              "_id": {"_id": "$users.user_id"},
              "users": {"$push": "$users"},
              "total": {"$sum": {"$cond": [{"$regexMatch": {"input": "$users.email", "regex": /filtered/}},1,0]}}
            }
        },
])

但是运行使用 PyMongo 的等效聚合，在 $regexMatch 中给出 OperationFailure:

pipeline = [
    {'$lookup': {'from': 'users', 'localField': '_id', 'foreignField': 'user_id', 'as': 'users'}}, 
    {'$unwind': '$users'}, 
    {'$group': {
        '_id': {'_id': '$users.user_id'},
        'users': {'$push': '$users'}, 
        'total': {'$sum': {'$cond': [{'$regexMatch': {'input': '$users.email', 'regex': re.compile('.*filtered.*', re.IGNORECASE)}}, 1, 0]}}}},
]

错误是：

  File "/Users/gcw/.pyenv/versions/3.7.6/envs/tt-api-env/lib/python3.7/site-packages/pymongo/collection.py", line 2380, in aggregate
    **kwargs)
  File "/Users/gcw/.pyenv/versions/3.7.6/envs/tt-api-env/lib/python3.7/site-packages/pymongo/collection.py", line 2299, in _aggregate
    retryable=not cmd._performs_write)
  File "/Users/gcw/.pyenv/versions/3.7.6/envs/tt-api-env/lib/python3.7/site-packages/pymongo/mongo_client.py", line 1464, in _retryable_read
    return func(session, server, sock_info, slave_ok)
  File "/Users/gcw/.pyenv/versions/3.7.6/envs/tt-api-env/lib/python3.7/site-packages/pymongo/aggregation.py", line 148, in get_cursor
    user_fields=self._user_fields)
  File "/Users/gcw/.pyenv/versions/3.7.6/envs/tt-api-env/lib/python3.7/site-packages/pymongo/pool.py", line 613, in command
    user_fields=user_fields)
  File "/Users/gcw/.pyenv/versions/3.7.6/envs/tt-api-env/lib/python3.7/site-packages/pymongo/network.py", line 167, in command
    parse_write_concern_error=parse_write_concern_error)
  File "/Users/gcw/.pyenv/versions/3.7.6/envs/tt-api-env/lib/python3.7/site-packages/pymongo/helpers.py", line 159, in _check_command_response
    raise OperationFailure(msg % errmsg, code, response)
pymongo.errors.OperationFailure: Failed to optimize pipeline :: caused by :: $regexMatch invalid flag in regex options: u

但是这个正则表达式选项 u 来自哪里？

Answer 1

我猜你正在做类似 Working with UTF-8 encoding in Python source 的事情来将源编码设置为 utf-8，这会将 unicode 标志添加到你的正则表达式中。

https://docs.mongodb.com/manual/reference/operator/aggregation/regexMatch/ 支持将正则表达式和选项指定为字符串而不是正则表达式对象。

Answer 2

通过使用 options 语法更改正则表达式定义，它起作用了。在 PyMongo 中的工作管道下方。

pipeline = [
    {'$lookup': {'from': 'users', 'localField': '_id', 'foreignField': 'user_id', 'as': 'users'}}, 
    {'$unwind': '$users'}, 
    {'$group': {
        '_id': {'_id': '$users.user_id'},
        'users': {'$push': '$users'}, 
        'total': {'$sum': {'$cond': [{"$regexMatch": {"input": "$users.email", "regex": ".*tiquetaque.*", "options": "i"}}, 1, 0]}}}},
]

Pymongo $regexMatch 正则表达式选项中的无效标志：u

Pymongo $regexMatch invalid flag in regex options: u

mongodb

pymongo

pymongo-3.x