ValueError: x 和 y 必须具有相同的第一维，但具有形状 (10, 1) 和 (90,)

Question

I'm learning ML from Udemy. From one of the lectures of Polynomial Regression, the following code is as follows:

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

# importing dataset
dataset = pd.read_csv("Position_Salaries.csv")
x = dataset.iloc[:, 1:2].values
y = dataset.iloc[:, 2].values
print(x.shape)
print(y.shape)
# fitting LR to the dataset
from sklearn.linear_model import LinearRegression
linreg = LinearRegression()
linreg.fit(x, y)

# fitting PR to the dataset
from sklearn.preprocessing import PolynomialFeatures
polreg = PolynomialFeatures(degree=2)
x_poly = polreg.fit_transform(x)
linreg2 = LinearRegression()
linreg2.fit(x_poly, y)


# visualising the polynomial regression results
x_grid = np.arange(min(x), max(x), 0.1)
x_grid = x_grid.reshape((len(x_grid), 1))
plt.scatter(x, y, color = "red")
plt.plot(x, linreg2.predict(polreg.fit_transform(x_grid)), color = "blue" )
plt.title("Truth or Bluff PR")
plt.xlabel("Position")
plt.ylabel("Salary")
plt.show()

I got error as follows:

Traceback (most recent call last):
  File "/home/ashutosh/Machine Learning A-Z Template Folder/Part 2 - Regression/Section 6 - Polynomial Regression/P14-Polynomial-Regression/Polynomial_Regression/plr.py", line 29, in <module>
    plt.plot(x, linreg2.predict(polreg.fit_transform(x_grid)), color = "blue" )
  File "/usr/local/lib/python3.7/dist-packages/matplotlib/pyplot.py", line 2795, in plot
    is not None else {}), **kwargs)
  File "/usr/local/lib/python3.7/dist-packages/matplotlib/axes/_axes.py", line 1666, in plot
    lines = [*self._get_lines(*args, data=data, **kwargs)]
  File "/usr/local/lib/python3.7/dist-packages/matplotlib/axes/_base.py", line 225, in __call__
    yield from self._plot_args(this, kwargs)
  File "/usr/local/lib/python3.7/dist-packages/matplotlib/axes/_base.py", line 391, in _plot_args
    x, y = self._xy_from_xy(x, y)
  File "/usr/local/lib/python3.7/dist-packages/matplotlib/axes/_base.py", line 270, in _xy_from_xy
    "have shapes {} and {}".format(x.shape, y.shape))
ValueError: x and y must have same first dimension, but have shapes (10, 1) and (90,)

the data set can be downloaded from here: https://sds-platform-private.s3-us-east-2.amazonaws.com/uploads/P14-Polynomial-Regression.zip

What can I do?

Answer 1

int the line 29, write x_grid instead of x ie, from

plt.plot(x, linreg2.predict(polreg.fit_transform(x_grid)), color = "blue" )

to

plt.plot(x_grid, linreg2.predict(polreg.fit_transform(x_grid)), color = "blue" )