产生元组的无意尾随逗号

Question

在Python中，这样的结尾逗号当然不是SyntaxError：

In [1]: x = 1 ,

In [2]: x
Out[2]: (1,)

In [3]: type(x)
Out[3]: tuple

但是，与此同时，如果 意外地用 了逗号结尾，可能很难抓住这种“问题”，尤其是对于Python新手。

我在想，是否可以借助智能代码质量控制功能 尽早地 静态地
解决这种“问题”PyCharm？mypy，pylint或flake8静态代码分析工具。

或者，另一个想法是 限制/突出显示隐式创建一个元组而没有括号 。可能吗？

Answer 1

pylint已经将其检测为问题（从1.7版开始）。

例如，这是我的tuple.py：

"""Module docstring to satisfy pylint"""

def main():
    """The main function"""
    thing = 1,
    print(type(thing))

if __name__ == "__main__":
    main()



$ pylint tuple.py
No config file found, using default configuration
************* Module tuple
R:  5, 0: Disallow trailing comma tuple (trailing-comma-tuple)

------------------------------------------------------------------
Your code has been rated at 8.00/10 (previous run: 8.00/10, +0.00)

$ pylint --help-msg trailing-comma-tuple
No config file found, using default configuration
:trailing-comma-tuple (R1707): *Disallow trailing comma tuple*
  In Python, a tuple is actually created by the comma symbol, not by the
  parentheses. Unfortunately, one can actually create a tuple by misplacing a
  trailing comma, which can lead to potential weird bugs in your code. You
  should always use parentheses explicitly for creating a tuple. This message
  belongs to the refactoring checker. It can't be emitted when using Python <
  3.0.