fit（）缺少1个必需的位置'y'

Question

I am practicing a sklearn modeling on load_iris data. When I initiate LogisticRegression from sklearn.linear_model I receive an error when I try to fit the data.

Below you may check my code:

      from sklearn.datasets import load_iris
      from sklearn.linear_model import LogisticRegression 

      logreg = LogisticRegression
      iris = load_iris()

      X = iris.data
      y = iris.target

      logreg.fit(X,y)

The code above prints out the following error:

fit() missing 1 required positional argument y

Any help would be appreciated!

Answer 1

You didn't instantiate LogisticRegression ; you forgot the parentheses:

logreg = LogisticRegression()

The error message arises because logreg.fit(X, y) can be thought of as syntactic sugar for LogisticRegression.fit(logreg, X, y) . Since logreg in your code is just another reference to the class, it is interpreting X as the required instance of LogisticRegression and y as the first argument; thus, the second argument does appear to be missing.