在python sklearn中出现“valueerror:应为2d数组,改为1d数组”错误

lh80um4z  于 2021-08-25  发布在  Java
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valueerror:应为2d数组,改为1d数组:(6个答案)
两天前关门了。
请帮帮我。我无法解决我遇到的一个错误。我是python机器学习新手。如果您对此有任何建议,我将不胜感激。
以下是我的代码,我编写该代码是为了根据公司员工的性别、学历和执照预测他们可能喜欢的交通方式:

Gender = preprocessing.LabelEncoder().fit_transform(df.loc[:,'Gender'])
Engineer = preprocessing.LabelEncoder().fit_transform(df.loc[:,'Engineer'])
MBA = preprocessing.LabelEncoder().fit_transform(df.loc[:,'MBA'])
License = preprocessing.LabelEncoder().fit_transform(df.loc[:,'license'])
Transport = preprocessing.LabelEncoder().fit_transform(df.loc[:,'Transport'])
x,y = Gender.reshape(-1,1), Transport
print("\n\nGender:", Gender, "\n\nEngineer:", Engineer, "\n\nMBA:", MBA, "\n\nLicense:", license, "\n\nTransport:", Transport)
model = GaussianNB().fit(x,y)
a1 = input("\n\n Choose Gender : Male:1 or Female:0 = ")
b1 = input("\n\n Are you an Engineer? : Yes:1 or No:0 = ")
c1 = input("\n\n Have you done MBA? : Yes:1 or No:0 = ")
d1 = input("\n\n Do you have license? : Yes:1 or No:0 = ")

# store the output in y_pred

y_pred = model = model.predict([int(a1),int(b1),int(c1),int(d1)])

# for loop to predict customizable output

if y_pred == [1]:
    print("\n\n You prefer Public Transport")
else:
    print("\n\n You prefer Private Transport")

这是我在最后阶段遇到的错误:

ValueError                                Traceback (most recent call last)
<ipython-input-104-a14f86182731> in <module>
      6 #store the output in y_pred
      7 
----> 8 y_pred = model = model.predict([int(a1),int(b1),int(c1),int(d1)])
      9 
     10 #for loop to predict customizable output

~\Anaconda3\lib\site-packages\sklearn\naive_bayes.py in predict(self, X)
     63             Predicted target values for X
     64         """
---> 65         jll = self._joint_log_likelihood(X)
     66         return self.classes_[np.argmax(jll, axis=1)]
     67 

~\Anaconda3\lib\site-packages\sklearn\naive_bayes.py in _joint_log_likelihood(self, X)
    428         check_is_fitted(self, "classes_")
    429 
--> 430         X = check_array(X)
    431         joint_log_likelihood = []
    432         for i in range(np.size(self.classes_)):

~\Anaconda3\lib\site-packages\sklearn\utils\validation.py in check_array(array, accept_sparse, accept_large_sparse, dtype, order, copy, force_all_finite, ensure_2d, allow_nd, ensure_min_samples, ensure_min_features, warn_on_dtype, estimator)
    519                     "Reshape your data either using array.reshape(-1, 1) if "
    520                     "your data has a single feature or array.reshape(1, -1) "
--> 521                     "if it contains a single sample.".format(array))
    522 
    523         # in the future np.flexible dtypes will be handled like object dtypes

ValueError: Expected 2D array, got 1D array instead:
array=[1 1 0 1].
Reshape your data either using array.reshape(-1, 1) if your data has a single feature or array.reshape(1, -1) if it contains a single sample.

以下是我的数据集的结构:

<class 'pandas.core.frame.DataFrame'>
    Int64Index: 444 entries, 28 to 39
    Data columns (total 8 columns):
    Gender       444 non-null object
    Engineer     444 non-null int64
    MBA          444 non-null int64
    Work Exp     444 non-null int64
    Salary       444 non-null float64
    Distance     444 non-null float64
    license      444 non-null int64
    Transport    444 non-null object
    dtypes: float64(2), int64(4), object(2)
    memory usage: 31.2+ KB
y4ekin9u

y4ekin9u1#

错误消息非常详细,并告诉您,您提供了一个1d数组,其中需要一个2d数组:
应为2d数组,改为1d数组
堆栈跟踪指向此行:

y_pred = model = model.predict([int(a1),int(b1),int(c1),int(d1)])

它还告诉您如何解决此问题:
使用数组重塑数据。如果数据具有单个特征或数组,则重塑(-1,1)。如果数据包含单个样本,则重塑(1,-1)。
由于您试图预测单个样本,因此应使用后者:

import numpy as np

y_pred = model.predict(np.array([int(a1),int(b1),int(c1),int(d1)]).reshape(1, -1))

注意,我删除了双重赋值 y_pred = model = ... 这是没有用的。
附加说明
与此特定错误无关,但可能不是您想要的:您只在性别特征上拟合模型。请参见以下几行:

x,y = Gender.reshape(-1,1), Transport
...
model = GaussianNB().fit(x,y)

当您在单个功能上拟合模型,然后想要预测具有四个功能的示例时,这将破坏您的代码。你也应该解决这个问题。解决方案可能如下所示:

X = OrdinalEncoder().fit_transform(df.loc[:,['Gender', 'Engineer', 'MBA', 'license']])
y = LabelEncoder().fit_transform(df.loc[:,'Transport'])

model = GaussianNB()
model.fit(X, y)

看看我用的 OrdinalEncoder 对于自 LabelEncoder 仅用于对目标进行编码 y (与文档进行比较)。

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