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not enough values to unpack (expected 3, got 1)

时间: 2023-09-04 17:07:56 浏览: 88

关于 Python opencv 使用中的 ValueError: too many values to unpack

最近在OpenCV-Python接口中使用cv2.findContours()函数来查找检测物体的轮廓。根据网上的教程，Python OpenCV的轮廓提取函数会返回两个值，第一个为轮廓的点集，第二个是各层轮廓的索引。但是实际调用时我的程序报错了，错误内容如下：too many values to unpack (expected 2) 其实是接受返回值不符，如果你仅仅使用一个变量a去接受返回值，调用len(a),你会发现长度为3，也就是说这个函数实际上返回了三个值第一个，也是最坑爹的一个，它返回了你所处理的图像第二个，正是我们要找的，轮廓的点集第三个，各层轮廓的索引使用方式如下：

This error message typically occurs when you are trying to unpack values from an iterable, but the number of values you are trying to unpack does not match the number of items in the iterable. For example, let's say you have the following code: ```python a, b, c = [1] ``` Here, you are trying to unpack three values from a list that only contains one item. Python will raise a "not enough values to unpack" error, because you are trying to unpack more values than there are items in the iterable. To fix this error, you need to make sure that the number of values you are trying to unpack matches the number of items in the iterable. For example, you could modify the above code to: ```python a, b, c = [1, 2, 3] ``` Here, you are unpacking three values from a list that contains three items, so Python will not raise an error.

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