ValueError: Expected 2D array, got scalar array instead using predict method

Question

I am trying to get a predicted value instead of whole features for a particular level using predict method.

import numpy as np
import pandas as pd
import matplotlib.pyplot as plt

#Importing Dataset
dataset = pd.read_csv('C:/Users/Rupali Singh/Desktop/ML A-Z/Machine Learning A-Z Template Folder/Part 2 - Regression/Section 7 - Support Vector Regression (SVR)/Position_Salaries.csv')
print(dataset)
X = dataset.iloc[:, 1:2].values
Y = dataset.iloc[:, 2].values

# Feature Scaling

from sklearn.preprocessing import StandardScaler

sc_X = StandardScaler()
sc_Y = StandardScaler()
X = sc_X.fit_transform(X)
Y = sc_Y.fit_transform(Y.reshape(-1,1))
#Fitting SVR model to dataset

from sklearn.svm import SVR

regressor = SVR(kernel='rbf')
regressor.fit(X,Y)

#Visualizing the dataset

plt.scatter(X, Y, color = 'red')
plt.plot(X, regressor.predict(X), color = 'blue')
plt.show()

# Predicting a new Result

Y_pred = regressor.predict(6.5)
print(Y_pred)

This is my dataset, here I am trying to predict value only for level 6

Position  Level   Salary
0   Business Analyst      1    45000
1  Junior Consultant      2    50000
2  Senior Consultant      3    60000
3            Manager      4    80000
4    Country Manager      5   110000
5     Region Manager      6   150000
6            Partner      7   200000
7     Senior Partner      8   300000
8            C-level      9   500000
9                CEO     10  1000000

This is the error message I am getting:

File "C:/Users/Rupali Singh/PycharmProjects/Machine_Learning/SVR.py", line 34, in <module>
    Y_pred = regressor.predict(6.5)
  File "C:\Users\Rupali Singh\PycharmProjects\Machine_Learning\venv\lib\site-packages\sklearn\svm\base.py", line 322, in predict
    X = self._validate_for_predict(X)
  File "C:\Users\Rupali Singh\PycharmProjects\Machine_Learning\venv\lib\site-packages\sklearn\svm\base.py", line 454, in _validate_for_predict
    accept_large_sparse=False)
  File "C:\Users\Rupali Singh\PycharmProjects\Machine_Learning\venv\lib\site-packages\sklearn\utils\validation.py", line 514, in check_array
    "if it contains a single sample.".format(array))
ValueError: Expected 2D array, got scalar array instead:
array=6.5.
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.

I would be really grateful for any kind of help.

Answer 1

Try:

Y_pred = regressor.predict(np.array([6.5]).reshape(1, 1))

Scikit does not work with scalars (just one single value). It expects a shape $(m\times n)$ where $m$ is the number of features and $n$ is the number of observations, both are 1 in your case.

Answer 2

Y_pred = regressor.predict([[6.5]])