如何以编程方式设置文档字符串?

问题描述

我有一个返回函数的包装函数.有没有办法以编程方式设置返回函数的文档字符串?如果我可以写信给 __doc__，我会执行以下操作:

def 包装器(a):def add_something(b):返回 a + badd_something.__doc__ = '将 ' + str(a) + ' 添加到 `b`'返回 add_something

那我就可以了

>>>add_three = 包装器(3)>>>add_three.__doc__'将 3 添加到 `b`

但是，由于 __doc__ 是只读的，我不能这样做.正确的做法是什么?

好的，我想保持简单，但这当然不是我真正想要做的.尽管通常 __doc__ 在我的情况下是可写的，但它不是.

我正在尝试自动为 unittest 创建测试用例.我有一个包装函数，它创建一个类对象，它是 unittest.TestCase 的子类:

导入单元测试def makeTestCase(文件名，my_func):类 ATest(unittest.TestCase):def testSomething(自我):# 使用文件名中的数据和函数 my_func 在此处运行测试数据 = loadmat(文件名)结果 = my_func(data)self.assertTrue(结果> 0)返回 ATest

如果我创建这个类并尝试设置 testSomething 的文档字符串，我会收到一个错误:

>>>def my_func(): 通过>>>MyTest = makeTestCase('some_filename', my_func)>>>MyTest.testSomething.__doc__ = '这应该是我的文档字符串'AttributeError: 'instancemethod' 对象的属性 '__doc__' 不可写

解决方案

我会将文档字符串传递给工厂函数并使用 type 手动构造类.

def make_testcase(filename, myfunc, docstring):def test_something(self):数据 = loadmat(文件名)结果 = myfunc(数据)self.assertTrue(结果> 0)clsdict = {'test_something': test_something,'__doc__':文档字符串}返回类型('ATest'，(unittest.TestCase，)，clsdict)MyTest = makeTestCase('some_filename', my_func, '这是一个文档字符串')

I have a wrapper function that returns a function. Is there a way to programmatically set the docstring of the returned function? If I could write to __doc__ I'd do the following:

def wrapper(a):
    def add_something(b):
       return a + b
    add_something.__doc__ = 'Adds ' + str(a) + ' to `b`'
    return add_something

Then I could do

>>> add_three = wrapper(3)
>>> add_three.__doc__
'Adds 3 to `b`

However, since __doc__ is read-only, I can't do that. What's the correct way?

---

Edit: Ok, I wanted to keep this simple, but of course this is not what I'm actually trying to do. Even though in general __doc__ is writeable in my case it isn't.

I am trying to create testcases for unittest automatically. I have a wrapper function that creates a class object that is a subclass of unittest.TestCase:

import unittest
def makeTestCase(filename, my_func):
    class ATest(unittest.TestCase):
        def testSomething(self):
            # Running test in here with data in filename and function my_func
            data  = loadmat(filename)
            result = my_func(data)
            self.assertTrue(result > 0)

    return ATest

If I create this class and try to set the docstring of testSomething I get an error:

>>> def my_func(): pass
>>> MyTest = makeTestCase('some_filename', my_func)
>>> MyTest.testSomething.__doc__ = 'This should be my docstring'
AttributeError: attribute '__doc__' of 'instancemethod' objects is not writable

解决方案

I would pass the docstring into the factory function and use type to manually construct the class.

def make_testcase(filename, myfunc, docstring):
    def test_something(self):
        data = loadmat(filename)
        result = myfunc(data)
        self.assertTrue(result > 0)

    clsdict = {'test_something': test_something,
               '__doc__': docstring}
    return type('ATest', (unittest.TestCase,), clsdict)

MyTest = makeTestCase('some_filename', my_func, 'This is a docstring')

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