Python 当需要一维数组时传递列向量 y
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A column-vector y was passed when a 1d array was expected
提问by Klausos Klausos
I need to fit RandomForestRegressorfrom sklearn.ensemble.
我需要RandomForestRegressor从sklearn.ensemble.
forest = ensemble.RandomForestRegressor(**RF_tuned_parameters)
model = forest.fit(train_fold, train_y)
yhat = model.predict(test_fold)
This code always worked until I made some preprocessing of data (train_y).
The error message says:
这段代码一直有效，直到我对数据 ( train_y)进行了一些预处理。错误消息说：
DataConversionWarning: A column-vector y was passed when a 1d array was expected. Please change the shape of y to (n_samples,), for example using ravel().
model = forest.fit(train_fold, train_y)
DataConversionWarning：当需要一维数组时传递了列向量 y。请将 y 的形状更改为 (n_samples,)，例如使用 ravel()。
模型 = Forest.fit(train_fold, train_y)
Previously train_ywas a Series, now it's numpy array (it is a column-vector). If I apply train_y.ravel(), then it becomes a row vector and no error message appears, through the prediction step takes very long time (actually it never finishes...).
以前train_y是一个系列，现在是 numpy 数组（它是一个列向量）。如果我申请train_y.ravel()，那么它会变成一个行向量并且不会出现错误消息，通过预测步骤需要很长时间（实际上它永远不会完成......）。
In the docs of RandomForestRegressorI found that train_yshould be defined as y : array-like, shape = [n_samples] or [n_samples, n_outputs]Any idea how to solve this issue?
在RandomForestRegressor我发现的文档中，train_y应该定义为y : array-like, shape = [n_samples] or [n_samples, n_outputs]任何想法如何解决这个问题？
回答by Linda MacPhee-Cobb
Change this line:
改变这一行：
model = forest.fit(train_fold, train_y)
to:
到：
model = forest.fit(train_fold, train_y.values.ravel())
Edit:
编辑：
.valueswill give the values in an array. (shape: (n,1)
.values将给出数组中的值。（形状：（n,1）
.ravelwill convert that array shape to (n, )
.ravel将该数组形状转换为 (n, )
回答by Coral
use below code:
使用以下代码：
model = forest.fit(train_fold, train_y.ravel())
if you are still getting slap by error as identical as below ?
如果您仍然被错误地打耳光，如下所示？
Unknown label type: %r" % y
use this code:
使用此代码：
y = train_y.ravel()
train_y = np.array(y).astype(int)
model = forest.fit(train_fold, train_y)
回答by Simon Leung
I also encountered this situation when I was trying to train a KNNclassifier. but it seems that the warning was gone after I changed:knn.fit(X_train,y_train)
toknn.fit(X_train, np.ravel(y_train,order='C'))
我在尝试训练KNN分类器时也遇到过这种情况。但似乎在警告不见了，我改变之后：knn.fit(X_train,y_train)
以knn.fit(X_train, np.ravel(y_train,order='C'))
Ahead of this line I used import numpy as np.
在这条线之前，我使用了import numpy as np.
回答by sushmit
Another way of doing this is to use ravel
另一种方法是使用 ravel
model = forest.fit(train_fold, train_y.values.reshape(-1,))
回答by mohammad hassan bigdeli shamlo
I had the same problem. The problem was that the labels were in a column format while it expected it in a row.
use np.ravel()
我有同样的问题。问题是标签是列格式，而它期望它排成一行。用np.ravel()
knn.score(training_set, np.ravel(training_labels))
Hope this solves it.
希望这能解决它。
回答by AlexB
With neuraxle, you can easily solve this :
使用neuraxle，您可以轻松解决这个问题：
p = Pipeline([
# expected outputs shape: (n, 1)
OutputTransformerWrapper(NumpyRavel()),
# expected outputs shape: (n, )
RandomForestRegressor(**RF_tuned_parameters)
])
p, outputs = p.fit_transform(data_inputs, expected_outputs)
Neuraxle is a sklearn-like framework for hyperparameter tuning and AutoML in deep learning projects !
Neuraxle 是一个类似于 sklearn 的框架，用于深度学习项目中的超参数调整和 AutoML！
回答by Bibby Wang
format_train_y=[]
for n in train_y:
format_train_y.append(n[0])
