本文介绍了从numpy数组中随机选择的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有两个相关的numpy数组,X
和y
.我需要从X
中选择n
个随机行,并将其存储在数组中,并存储相应的y
值,并在其后追加随机选择的点的索引.
I have two related numpy arrays, X
and y
. I need to select n
random rows from X
and store this in an array, the corresponding y
value and the appends to it the index of the points randomly selected.
我还有另一个数组index
,它存储了我不想采样的索引列表.
I have another array index
which stores a list of index which I dont want to sample.
我该怎么做?
样本数据:
index = [2,3]
X = np.array([[0.3,0.7],[0.5,0.5] ,[0.2,0.8], [0.1,0.9]])
y = np.array([[0], [1], [0], [1]])
如果随机选择了这些X
(其中n=2
):
If these X
's were randomly selected (where n=2
):
randomylSelected = np.array([[0.3,0.7],[0.5,0.5]])
所需的输出将是:
index = [0,1,2,3]
randomlySelectedY = [0,1]
我该怎么做?
推荐答案
您可以使用 np.random.choice
:
You can create random indices with np.random.choice
:
n = 2 # for 2 random indices
index = np.random.choice(X.shape[0], n, replace=False)
然后,您只需要使用结果对数组进行索引:
Then you just need to index your arrays with the result:
x_random = X[index]
y_random = Y[index]
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