Question

我正在使用泰坦尼克号数据集在Kaggle上练习R. 我正在使用随机森林Algorthim

以下是代码

public static void writeFile(String fileName, String encoding, String payload) {
    try (BufferedWriter writer = new BufferedWriter(
            new OutputStreamWriter(getStream(fileName, encoding, payload), encoding))) {
        writer.write(payload);
    } catch (IOException e) {
        e.printStackTrace();
    }
}

public static OutputStream getStream(String fileName, String encoding, String payload) throws IOException {
    boolean needGzip = payload.getBytes(encoding).length > gzipZize;
    File output = needGzip ? new File(fileName + ".gz") : new File(fileName);
    return needGzip ? new GZIPOutputStream(new FileOutputStream(output)) : new FileOutputStream(output);
}

我收到以下错误

fit <- randomForest(as.factor(Survived) ~ Pclass + Sex + Age_Bucket + Embarked
                + Age_Bucket + Fare_Bucket + F_Name + Title + FamilySize + FamilyID, 
                data=train, importance=TRUE, ntree=5000)

我的数据如下所示

Error in randomForest.default(m, y, ...) : 
  NA/NaN/Inf in foreign function call (arg 1)
In addition: Warning messages:
1: In data.matrix(x) : NAs introduced by coercion
2: In data.matrix(x) : NAs introduced by coercion
3: In data.matrix(x) : NAs introduced by coercion
4: In data.matrix(x) : NAs introduced by coercion

如果我只输入以下内容，我没有强制性问题，据我所知，这是唯一一个强制发生NA值的地方

$ Survived   : int  0 1 1 1 0 0 0 0 1 1 ...
$ Pclass     : int  3 1 3 1 3 3 1 3 3 2 ...
$ Sex        : Factor w/ 2 levels "female","male": 2 1 1 1 2 2 2 2 1 1...
$ Age_Bucket : chr  "20-25" "30-40" "25-30" "30-40" ...
$ Fare_Bucket: chr  "<10" "30+" "<10" "30+" ...
$ Title      : Factor w/ 11 levels "Col","Dr","Lady",..: 7 8 5 8 7 7 7 4 8 8 ...
$ F_Name     : chr  "Braund" "Cumings" "Heikkinen" "Futrelle" ...
$ FamilySize : num  2 2 1 2 1 1 1 5 3 2 ...
$ Embarked   : Factor w/ 3 levels "C","Q","S": 3 1 3 3 3 2 3 3 3 1 ...
$ FamilyID   : chr  "Small" "Small" "Alone" "Small" ...

任何人都可以看到问题

感谢您的时间

Answer 1

您需要将char列转换为因子。因子在内部被视为整数而字符字段则不是。请参阅以下小型演示：

数据：

df <- data.frame(y = sample(0:1, 26, rep=T), x1=runif(26), x2=letters, stringsAsFactors=F) df$y <- as.factor(df$y) > str(df) 'data.frame': 26 obs. of 3 variables: $ y : Factor w/ 2 levels "0","1": 1 1 1 1 1 1 1 2 2 1 ... $ x1: num 0.457 0.296 0.517 0.478 0.764 ... $ x2: chr "a" "b" "c" "d" ...

现在，如果我运行randomForest函数：

> randomForest(y ~ x1 + x2, data=df) Error in randomForest.default(m, y, ...) : NA/NaN/Inf in foreign function call (arg 1) In addition: Warning message: In data.matrix(x) : NAs introduced by coercion

我遇到了同样的错误。

然而，如果我将char列转换为factor：

df$x2 <- as.factor(df$x2) > randomForest(y ~ x1 + x2, data=df) Call: randomForest(formula = y ~ x1 + x2, data = df) Type of random forest: classification Number of trees: 500 No. of variables tried at each split: 1 OOB estimate of error rate: 61.54% Confusion matrix: 0 1 class.error 0 0 16 1 1 0 10 0

效果很好！

R：由强制引入的Kaggle Titanic数据集随机森林NA

1 个答案: