我得到了错误,不知道如何解决它。你能帮忙吗。整个代码可以在https://github.com/kthouz/NYC_Green_Taxi/blob/master/NYC%20Green%20Taxi.ipynb找到
def optimize_num_trees(alg,param_test,scoring_method,train,predictors,target):
"""
This functions is used to tune paremeters of a predictive algorithm
alg: sklearn model,
param_test: dict, parameters to be tuned
scoring_method: str, method to be used by the cross-validation to valuate the model
train: pandas.DataFrame, training data
predictors: list, labels to be used in the model training process. They should be in the column names of dtrain
target: str, target variable
"""
gsearch = GridSearchCV(estimator=alg, param_grid = param_test, scoring=scoring_method,n_jobs=2,iid=False,cv=5)
gsearch.fit(train[predictors],train[target])
return gsearch
# get results of the search grid
gs_cls = optimize_num_trees(model_cls,param_test,'roc_auc',train,predictors,target)
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
<ipython-input-42-c7419a90cdb1> in <module>()
1
2 # get results of the search grid
----> 3 gs_cls = optimize_num_trees(model_cls,param_test,'roc_auc',train,predictors,target)
4
<ipython-input-40-2b76f2ffb87f> in optimize_num_trees(alg, param_test, scoring_method, train, predictors, target)
57 target: str, target variable
58 """
---> 59 gsearch = GridSearchCV(estimator=alg, param_grid = param_test, scoring=scoring_method,n_jobs=2,iid=False,cv=5)
60 gsearch.fit(train[predictors],train[target])
61 return gsearch
/Users/anaconda/lib/python3.5/site-packages/sklearn/grid_search.py in __init__(self, estimator, param_grid, scoring, fit_params, n_jobs, iid, refit, cv, verbose, pre_dispatch, error_score)
810 refit, cv, verbose, pre_dispatch, error_score)
811 self.param_grid = param_grid
--> 812 _check_param_grid(param_grid)
813
814 def fit(self, X, y=None):
/Users/anaconda/lib/python3.5/site-packages/sklearn/grid_search.py in _check_param_grid(param_grid)
346 if True not in check:
347 raise ValueError("Parameter values for parameter ({0}) need "
--> 348 "to be a sequence.".format(name))
349
350 if len(v) == 0:
ValueError: Parameter values for parameter (n_estimators) need to be a sequence.
GridSearchCV要求参数值采用序列格式,因此即使参数值是单个值,也应始终以列表或numpy数组的形式给出参数值。
例如: 如果为GridSearchCV提供下面的字典,则会引发错误,因为n_jobs-1的值是单个整数,而不是序列(列表或数组)。
参数={'alpha':[0.01,0.1,1,10],'n_作业':-1}
但是如果您将-1包装在一个列表中,并将其交给GridSearchCV,则不会产生任何错误。 参数={'alpha':[0.01,0.1,1,10],'n_作业':[-1]}
希望有帮助。
我犯了和你类似的错误:
每个键的值显然需要放在数组方括号内[]
我的错误代码:
我的正确代码:
在下面的代码中,我遇到了类似的错误:
你可以改变
从
range(30,151,20)
到np.arange(30,151,20)
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