各位大佬有知道randomforest如何输出带有prediction概率的结果

0
2016-12-08 添加评论
分享

没有找到相关结果

    已邀请:
    1

    marxsong 2016-12-14 回答

    你好，randomForest的predict函数中有个type参数可以设置，
    type：
    one of response, prob. or votes, indicating the type of output: predicted values, matrix of class probabilities, or matrix of vote counts. class is allowed, but automatically converted to "response", for backward compatibility.
    "predict"(object, newdata, type="response", norm.votes=TRUE, predict.all=FALSE, proximity=FALSE, nodes=FALSE, cutoff, ...)
    你要输出为概率值，则只需要令type = 'prob'
    举个例子：
    library(randomForest)
    
data(iris)
    
set.seed(111)
    
ind <- sample(2, nrow(iris), replace = TRUE, prob=c(0.8, 0.2))
    
iris.rf <- randomForest(Species ~ ., data=iris[ind == 1,])
    
> predict(iris.rf, iris[ind == 2,])
    
        18         25         40         44         48         55         60         65         71         78 
    
    setosa     setosa     setosa     setosa     setosa versicolor versicolor versicolor  virginica  virginica 
    
        82         92         97         99        100        103        105        110        113        114 
    
versicolor versicolor versicolor versicolor versicolor  virginica  virginica  virginica  virginica  virginica 
    
       115        118        123        127        128        129        134        139        141        142 
    
 virginica  virginica  virginica  virginica  virginica  virginica versicolor  virginica  virginica  virginica 
    
Levels: setosa versicolor virginica
    
> predict(iris.rf, iris[ind == 2,],type = 'prob')
    
    setosa versicolor virginica
    
18   1.000      0.000     0.000
    
25   1.000      0.000     0.000
    
40   1.000      0.000     0.000
    
44   1.000      0.000     0.000
    
48   1.000      0.000     0.000
    
55   0.000      0.994     0.006
    
60   0.004      0.964     0.032
    
65   0.000      1.000     0.000
    
71   0.002      0.342     0.656
    
78   0.000      0.282     0.718
    
82   0.000      1.000     0.000
    
92   0.000      0.994     0.006
    
97   0.000      1.000     0.000
    
99   0.000      0.976     0.024
    
100  0.000      1.000     0.000
    
103  0.000      0.002     0.998
    
105  0.000      0.000     1.000
    
110  0.008      0.000     0.992
    
113  0.000      0.002     0.998
    
114  0.000      0.042     0.958
    
115  0.000      0.010     0.990
    
118  0.008      0.000     0.992
    
123  0.000      0.002     0.998
    
127  0.000      0.336     0.664
    
128  0.000      0.128     0.872
    
129  0.000      0.002     0.998
    
134  0.000      0.558     0.442
    
139  0.000      0.346     0.654
    
141  0.000      0.000     1.000
    
142  0.000      0.024     0.976
    2016-12-14 0
    分享
    为什么被折叠? 0 个回复被折叠

    要回复问题请先登录或注册