ValueError: Expected 2D array, got scalar array instead: array=750

Question

import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
import seaborn as sns
sns.set()
from sklearn.linear_model import LinearRegression

data=pd.read_csv('real_estate_price_size.csv')
y=data['price']
x=data['size']
y.shape
x.shape

both out put is same (100,)

x_matrix = x.values.reshape(-1,1)
reg = LinearRegression()
reg.fit(x_matrix,y)    
reg.predict(750)

when i run this i get error as

ValueError: Expected 2D array, got scalar array instead:
array=750.
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 cant under stand what to do i tried reshaping it but it dint work out.

and (2) previously when i typed

reg = LinearRegression()
reg.fit(x_matrix,y)

i used to get output like this

LinearRegression(copy_X=True, fit_intercept=True, n_jobs=1, normalize=False)

now i just get text like

 LinearRegression()

help would be much appriciated .

Answer 1

You are missing a dimension. Your prediction input should have the shape (n_samples, n_features). Try something like this:

import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
import seaborn as sns
sns.set()
from sklearn.linear_model import LinearRegression

y=np.random.random((100, 1))
x=np.random.random((100, 1))

reg = LinearRegression()
reg.fit(x,y)
    
predict_input = np.array([[750]])
predict_input.shape
reg.predict(predict_input)

(1, 1)
array([[-26.07506481]])