Python 类型错误：'numpy.float64' 对象不支持项目分配
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TypeError: 'numpy.float64' object does not support item assignment
提问by chen
def classify(self, texts):
vectors = self.dictionary.feature_vectors(texts)
predictions = self.svm.decision_function(vectors)
predictions = np.transpose(predictions)[0]
predictions = predictions / 2 + 0.5
predictions[predictions > 1] = 1
predictions[predictions < 0] = 0
return predictions
The error:
错误：
TypeError: 'numpy.float64' object does not support item assignment
occurs on the following line:
发生在以下行：
predictions[predictions > 1] = 1
Does anyone has an idea of solving this problem? Thanks!
有没有人有解决这个问题的想法？谢谢！
回答by Max Tkachenko
Try this testing code and pay attention to np.array([1,2,3], dtype=np.float64).
It seems self.svm.decision_function(vectors) returns 1darray instead of 2d.
If you replace [1,2,3] to [[1,2,3], [4,5,6]] everything will be ok.
试试这个测试代码并注意np.array([1,2,3], dtype=np.float64). 这似乎self.svm.decision_function（载体）返回1D阵列而不是2D。如果将 [1,2,3] 替换为 [[1,2,3], [4,5,6]] 一切都会好的。
import numpy as np
predictions = np.array([1,2,3], dtype=np.float64)
predictions = np.transpose(predictions)[0]
predictions = predictions / 2 + 0.5
predictions[predictions > 1] = 1
predictions[predictions < 0] = 0
Output:
输出：
Traceback (most recent call last):
File "D:\temp\test.py", line 7, in <module>
predictions[predictions > 1] = 1
TypeError: 'numpy.float64' object does not support item assignment
So, what your vectors are?
那么，你的向量是什么？
回答by john ktejik
predictions > 1
is a boolean operation.
是一个布尔运算。
predictions[predictions > 1] = 1
evaluates to
评估为
predictions[True]
You are looking for the np.where()operator. Your code should look like this:
您正在寻找np.where()运算符。您的代码应如下所示：
predictions[np.where(predictions > 1)] = 1
回答by Danny Wu
>>> predictions = np.array([1,2,3], dtype=np.float64)
>>> predictions
array([1., 2., 3.])
>>> predictions = np.transpose(predictions)[0]
>>> predictions
1.0
>>> predictions = predictions / 2 + 0.5
>>> predictions
1.0
>>> predictions>1
False
there is no element in array is bigger than 1,So you cannot assign 1 to predictions[predictions>1],you can use ' predictions>1 ' before your assignment.
数组中没有元素大于 1，因此您不能将 1 分配给预测 [predictions>1]，您可以在分配之前使用 'predictions>1'。
回答by Sibulele
You can't perform this operation in all elements at once,
您不能一次在所有元素中执行此操作，
predictions = predictions / 2 + 0.5
预测 = 预测 / 2 + 0.5
If you want to update all the elements contained by 'predictions', rather do the following
如果要更新“预测”包含的所有元素，请执行以下操作
for i in range(predictions):
predictions[i] = predictions[i] / 2 + 0.5
What are you doing here ???????????
你在这里做什么 ？？？？？？？？？？？
predictions[predictions > 1] = 1
预测[预测 > 1] = 1
I am not sure of what you are trying to do , but if you are trying to compare if elements at each index of 'predictions' is greater than 1, rather put the statements under the above if statement as follows
我不确定您要做什么，但是如果您要比较“预测”的每个索引处的元素是否大于 1，请将语句放在上面的 if 语句下，如下所示
for i in range(predictions):
predictions[i] = predictions[i] / 2 + 0.5
if predictions[i] > 1:
predictions[i] = 1
elif predictions[i] < 0 :
predictions[i] = 0
return predictions
