如何使用VowpalWabbit python框架学习多行示例？

Question

from vowpalwabbit import pyvw
vw = pyvw.vw("--cb 3 --epsilon 0.2 --quiet")
input = "2:-5:0.2 |  Anna" 
vw.learn(input)
input = "3:-20:0.2 | Anna \n 2:-20:0.2 | Anna \n 1:-20:0.2 | Anna"
vw.learn([vw.example(string) for string in input.split('\n')])
print(vw.predict(" | Anna"))

这段代码抛出了错误：

RuntimeError                              Traceback (most recent call last)

<ipython-input-7-e8693ac0708c> in <module>()
      4 vw.learn(input)
      5 input = "3:-20:0.2 | Anna \n 2:-20:0.2 | Anna \n 1:-20:0.2 | Anna"
----> 6 vw.learn([vw.example(string) for string in input.split('\n')])
      7 
      8 vw.learn(input)

/usr/local/lib/python3.6/dist-packages/vowpalwabbit/pyvw.py in learn(self, ec)
    168             pylibvw.vw.learn(self, ec)
    169         elif isinstance(ec, list):
--> 170             pylibvw.vw.learn_multi(self,ec)
    171         else:
    172             raise TypeError('expecting string or example object as ec argument for learn, got %s' % type(ec))

RuntimeError: This reduction does not support multi-line example.

为什么我会得到这个错误？从多行示例中学习的正确语法是什么？

Answer 1

问题是，您正在使用的缩减CB是单行缩减。因此，在这种情况下，传递多行示例没有意义。这可以从以下错误中看出：

RuntimeError: This reduction does not support multi-line example.

你可以在这里阅读更多关于--cb的信息：https://github.com/VowpalWabbit/vowpal_wabbit/wiki/Logged-Contextual-Bandit-Example