python - Scikit set_params()

Question

我想使用 set_params() 设置 SVC 的参数，如以下示例代码所示。

from sklearn.svm import SVC

params = {'C': [.1, 1, 10]}

for k, v in params.items():
    for val in v:
        clf = SVC().set_params(k=val)
        print(clf)
        print()

如果我运行代码，我会收到以下错误:

ValueError: Invalid parameter k for estimator SVC

如何将 key 正确地放入 set_params()？

Answer 1

问题实际上是如何使用字符串作为关键字参数。您可以使用 ** 语法构造一个参数字典并将其传递给 set_params。

from sklearn.svm import SVC

params = {'C': [.1, 1, 10]}

for k, v in params.items():
    for val in v:
        clf = SVC().set_params(**{k: val})
        print(clf)
        print()

输出:

SVC(C=0.1, cache_size=200, class_weight=None, coef0=0.0, degree=3, gamma=0.0,
  kernel='rbf', max_iter=-1, probability=False, random_state=None,
  shrinking=True, tol=0.001, verbose=False)

SVC(C=1, cache_size=200, class_weight=None, coef0=0.0, degree=3, gamma=0.0,
  kernel='rbf', max_iter=-1, probability=False, random_state=None,
  shrinking=True, tol=0.001, verbose=False)

SVC(C=10, cache_size=200, class_weight=None, coef0=0.0, degree=3, gamma=0.0,
  kernel='rbf', max_iter=-1, probability=False, random_state=None,
  shrinking=True, tol=0.001, verbose=False)