ظهور الخطأ التالي Expected 2D array, got 1D array instead عند محاولة تدريب نموذج في مكتبة Sklearn

عند محاولة تدريب model ( نموذج ) يظهر لي الخطأ التالي Expected 2D array, got 1D array instead  الكود:

from sklearn.preprocessing  import LabelEncoder
import pandas as pd
from sklearn.model_selection import train_test_split
from sklearn.linear_model import LinearRegression
# إنشاءداتا 
data = {'size': [100, 30, 50, 200, 2],
        'class': ['big', 'small', 'medium', 'verybig', 'verysmall']}
df = pd.DataFrame(data)
le = LabelEncoder()
le.fit(df['class'])
df['class'] = le.transform(df['class'])
X_train, X_test, y_train, y_test = train_test_split(df['size'], df['class'], random_state = 42, test_size = 0.33)
linreg = LinearRegression()
linreg.fit(X_train, y_train)
linreg.score(x_test,y_test)
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-9-f740a0daa981> in <module>
     12 X_train, X_test, y_train, y_test = train_test_split(df['size'], df['class'], random_state = 42, test_size = 0.33)
     13 linreg = LinearRegression()
---> 14 linreg.fit(X_train, y_train)
     15 linreg.score(x_test,y_test)

~\anaconda3\lib\site-packages\sklearn\linear_model\_base.py in fit(self, X, y, sample_weight)
    490         n_jobs_ = self.n_jobs
    491         X, y = check_X_y(X, y, accept_sparse=['csr', 'csc', 'coo'],
--> 492                          y_numeric=True, multi_output=True)
    493 
    494         if sample_weight is not None:

~\anaconda3\lib\site-packages\sklearn\utils\validation.py in check_X_y(X, y, accept_sparse, accept_large_sparse, dtype, order, copy, force_all_finite, ensure_2d, allow_nd, multi_output, ensure_min_samples, ensure_min_features, y_numeric, warn_on_dtype, estimator)
    753                     ensure_min_features=ensure_min_features,
    754                     warn_on_dtype=warn_on_dtype,
--> 755                     estimator=estimator)
    756     if multi_output:
    757         y = check_array(y, 'csr', force_all_finite=True, ensure_2d=False,

~\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)
    554                     "Reshape your data either using array.reshape(-1, 1) if "
    555                     "your data has a single feature or array.reshape(1, -1) "
--> 556                     "if it contains a single sample.".format(array))
    557 
    558         # in the future np.flexible dtypes will be handled like object dtypes

ValueError: Expected 2D array, got 1D array instead:
array=[ 50 100 200].