NameError: name 'classname' is not defined error in python

Question

I was working on a python program. I have created a class named "Perception". The code is given below:

 import numpy as np class Perceptron(object): def __init__(self, eta=0.01, n_iter=10): self.eta=eta self.n_iter=n_iter def fit(self, X, y): self.w_=np.zeros(1+X.shape[1]) self.errors_ = [] for _ in range(self.n_iter): errors =0 for xi,target in zip(X,y): update = self.eta * (target - self.predict(xi)) self.w_[1:] += update * xi self.w_[0] += update errors += int(update != 0.0) self.errors_.append(errors) return self def net_input(self, X): """Calculate net input""" return np.dot(X, self.w_[1:]) + self.w_[0] def predict(self, X): """Return class label after unit step""" return np.where(self.net_input(X) >= 0.0, 1, -1) 

when i want to declare the class in the following line:

ppn = Perceptron(eta=0.1, n_iter=10)

I get the following error:

NameError: name 'Perceptron' is not defined

I am new to Python. Please help me in the next steps. And Thanks in advance.

Answer 1

Run this it should work , if not share the screen hot of code and output.
import numpy as np
class Perceptron(object):

    def __init__(self, eta=0.01, n_iter=10):
        self.eta=eta
        self.n_iter=n_iter


    def fit(self, X, y):
        self.w_=np.zeros(1+X.shape[1])
        self.errors_ = []

        for _ in range(self.n_iter):
            errors =0
            for xi,target in zip(X,y):
                update = self.eta * (target - self.predict(xi))
                self.w_[1:] += update * xi
                self.w_[0] += update
                errors += int(update != 0.0)
            self.errors_.append(errors)
        return self

    def net_input(self, X):
        """Calculate net input"""
        return np.dot(X, self.w_[1:]) + self.w_[0]

    def predict(self, X):
        """Return class label after unit step"""
        return np.where(self.net_input(X) >= 0.0, 1, -1)



ppn = Perceptron(eta=0.1, n_iter=10)

Answer 2

您应该调用ppn = Perceptron.Perceptron（eta = 0.1，n_iter = 10）