[英]Difference between accuracy_score in scikit-learn and accuracy in Keras
[英]“Invalid Index to Scalar Variable” - When Using Scikit Learn “accuracy_score”
不确定到底出了什么问题。 但是,我的目标是建立一个交叉验证python代码。 我知道有各种指标,但是我认为我使用的是正确的指标。 我没有得到我想要的CV10结果,而是收到一个错误:
“标量变量的无效索引”
我在StackOverflow上发现了此问题: IndexError:当您尝试索引numpy标量(例如numpy.int64或numpy.float64)时,对标量变量的索引无效。 它与TypeError非常相似:当您尝试为一个int索引时,“ int”对象没有属性“ _ getitem _”。
任何帮助,将不胜感激...
我正在尝试遵循:: http://scikit-learn.org/stable/modules/model_evaluation.html
from sklearn.ensemble import RandomForestClassifier
from sklearn import cross_validation
from numpy import genfromtxt
import numpy as np
from sklearn.metrics import accuracy_score
def main():
#read in data, parse into training and target sets
dataset = genfromtxt(open('D:\\CA_DataPrediction_TrainData\\CA_DataPrediction_TrainDataGenetic.csv','r'), delimiter=',', dtype='f8')[1:]
target = np.array( [x[0] for x in dataset] )
train = np.array( [x[1:] for x in dataset] )
#In this case we'll use a random forest, but this could be any classifier
cfr = RandomForestClassifier(n_estimators=10)
#Simple K-Fold cross validation. 10 folds.
cv = cross_validation.KFold(len(train), k=10, indices=False)
#iterate through the training and test cross validation segments and
#run the classifier on each one, aggregating the results into a list
results = []
for traincv, testcv in cv:
pred = cfr.fit(train[traincv], target[traincv]).predict(train[testcv])
results.append(accuracy_score(target[testcv], [x[1] for x in pred]) )
#print out the mean of the cross-validated results
print "Results: " + str( np.array(results).mean() )
if __name__=="__main__":
main()
您的pred
变量只是预测的列表,因此您无法为其元素编制索引(这就是错误的原因)
results.append(accuracy_score(target[testcv], [x[1] for x in pred]) )
应该
results.append(accuracy_score(target[testcv], pred) )
或者如果您真的想要副本
results.append(accuracy_score(target[testcv], [x for x in pred]) )
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