July 2019
Intermediate to advanced
365 pages
8h 13m
Chinese
Content preview from Python机器学习手册：从数据预处理到深度学习
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20.3
训练一个二元分类器
｜
307
延伸阅读
y
Keras
文档 ：损失函数（
https://keras.io/losses/
）
y
分类的损失函数（
Wikipedia
，
http://bit.ly/2FwpCkM
）
y
《分类问题中深度神经网络的损失函数》（
Katarzyna Jano cha, Wojciech Marian
Czarnecki
，
https://arxiv.org/abs/1702.05659
）
20.3
训练一个二元分类器
问题描述
训练一个二元分类的神经网络。
解决方案
使用
Keras
构建一个前馈神经网络，然后用
t
方法训练它 ：
#
加载库
import numpy as np
from keras.datasets import imdb
from keras.preprocessing.text import Tokenizer
from keras import models
from keras import layers
#
设定随机种子
np.random.seed(0)
#
设定想要的特征数量
number_of_features = 1000
#
从影评数据中加载数据和目标向量
(data_train, target_train), (data_test, target_test) = imdb.load_data(
num_words=number_of_features)
#
将影评数据转化为
one-hot
编码过的特征矩阵
tokenizer ...
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