Expected 2D array, got 1D array instead error

Question

Iam getting the error as

"ValueError: Expected 2D array, got 1D array instead: array=[ 45000. 50000. 60000. 80000. 110000. 150000. 200000. 300000. 500000. 1000000.]. 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."

while executing the following code:

# SVR

# Importing the libraries
import numpy as np
import matplotlib.pyplot as plt
import pandas as pd

# Importing the dataset
dataset = pd.read_csv('Position_S.csv')
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)

# Fitting SVR to the dataset
from sklearn.svm import SVR
regressor = SVR(kernel = 'rbf')
regressor.fit(X, y)

# Visualising the SVR results
plt.scatter(X, y, color = 'red')
plt.plot(X, regressor.predict(X), color = 'blue')
plt.title('Truth or Bluff (SVR)')
plt.xlabel('Position level')
plt.ylabel('Salary')
plt.show()

# Visualising the SVR results (for higher resolution and smoother curve)
X_grid = np.arange(min(X), max(X), 0.01)
X_grid = X_grid.reshape((len(X_grid), 1))
plt.scatter(X, y, color = 'red')
plt.plot(X_grid, regressor.predict(X_grid), color = 'blue')
plt.title('Truth or Bluff (SVR)')
plt.xlabel('Position level')
plt.ylabel('Salary')
plt.show()

Solution

Seems, expected dimension is wrong. Could you try:

regressor = SVR(kernel='rbf')
regressor.fit(X.reshape(-1, 1), y)

Comments

[aroN]

could u please tell what does this x.reshape(-1,1).actually do.It also solves the problem.I actually solved it by changing into y = dataset.iloc[:, 2:3].values eventhough i gave only 3 columns.

[Danylo Baibak]

According to the error message, you have input data in the format [45000, 50000, 60000, ...]. But the model expects the input in the format like [[45000], [50000], [60000], ...] - a list of the lists. So reshape(-1, 1) just changes a format.

[Pavindu]

Note that reshape() is now deprecated. use df.values.reshape() instead.