小编mr_*_*thi的帖子

在我的办公室计算机上，我已经virtualenv one-for-rule-them-all在Dropbox文件夹中创建了。我想在办公室和家里都使用这种环境。这可能吗？（当前我不成功）

>>> d = {}
>>> s = str(d)
>>> print s
{}

我需要一个空字符串.

我知道有几个非常相似的主题，但每个主题都有独特的 clang 回溯，我的情况也不例外。

我的 macOS 版本是 Mojave 10.14.2。我安装了命令行工具，$ echo $C_INCLUDE_PATH输出/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk/usr/include

所以我尝试通过安装 lxml pip install lxml，并获得以下回溯：

Running setup.py bdist_wheel for lxml ... error
  Complete output from command /Users/bulrathi/Virtualenvs/gm-test/bin/python3.7 -u -c "import setuptools, tokenize;__file__='/private/var/folders/4n/brsfjpqx0kz8lh4rdcz6nb0w0000gn/T/pip-install-8a1v9j7p/lxml/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" bdist_wheel -d /private/var/folders/4n/brsfjpqx0kz8lh4rdcz6nb0w0000gn/T/pip-wheel-wpeizpmd --python-tag cp37:
  Building lxml version 3.6.0.
  Building without Cython.
  Using build configuration of libxslt 1.1.29
  Building against libxml2/libxslt in the following directory: /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk/usr/lib
  running bdist_wheel
  running build
  running build_py
  creating build
  creating build/lib.macosx-10.14-x86_64-3.7
  creating build/lib.macosx-10.14-x86_64-3.7/lxml
  copying …

我对 sqlalchemy（以及 sql）真的很陌生，所以请不要开枪。

我有两个疑问：

user_logins_count = self.request.db.query(
    sa.func.count(UserSession.id)
).filter(
    sa.and_(
        UserSession.user_id == user_id,
        sa.between(UserSession.date_login_session, start_date, end_date)
    )
)

和

user_questions_count = self.request.db.query(
    sa.func.count(QuestionAnswer.id).label('questions_amount')
).filter(
    sa.and_(
        QuestionAnswer.user_id == user_id,
        sa.between(QuestionAnswer.created, start_date, end_date)
    )
)

是否可以有一个查询而不是这两个查询？

我有一个非常原始的 Flask 应用程序，它按我的预期工作，但我无法为其编写单元测试。该应用程序的代码如下（我省略了无关紧要的部分）：

app.py\n\nfrom flask import *\nimport random\nimport string\n\napp = Flask(__name__)\nkeys = []\napp.testing = True\n\n@app.route(\'/keygen/api/keys\', methods=[\'POST\'])\ndef create():\n    symbol = string.ascii_letters + string.digits\n    key = \'\'.join(random.choice(symbol) for _ in range(4))\n    key_instance = {\'key\': key, \'is_used\': False}\n    keys.append(key_instance)\n\n    return jsonify({\'keys\': keys}), 201\n

测试是：

tests.py\n\nimport unittest\nfrom flask import *\nimport app\n\nclass TestCase(unittest.TestCase):\n    def test_number_one(self):\n        test_app = Flask(app)\n        with test_app.test_client() as client:\n            rv = client.post(\'/keygen/api/keys\')\n\n        ...something...\n\n    if __name__ == \'__main__\':\n    unittest.main()\n

回溯：

ERROR: test_number_one (__main__.TestCase)\n----------------------------------------------------------------------\nTraceback (most recent call last):\n  File …