在Java中将字符串解析为双精度时出现错误

问题描述 投票:0回答:3

我正在尝试读取一个csv文件,并将其String值转换为double。

public void trq() throws IOException, ParseException {
    Test4 obj = new Test4();
    String path = "transposedData1.csv";
    BufferedReader readerBuffer = new BufferedReader(new FileReader(path));
    String line;
    List<Double> results = new ArrayList<Double>();
    while ((line = readerBuffer.readLine()) != null) {
        if(!line.contains("NA")) {
            ArrayList<String> data_per_class = convertCSVtoArrayList11(line);

            List<Double> doubleList = data_per_class.stream()
                    .map(Double::parseDouble)
                    .collect(Collectors.toList()); // the error here

            // do other things
        }
    }
}

public static ArrayList<String> convertCSVtoArrayList11(String pathCSV) {
    ArrayList<String> result = new ArrayList<String>();

    if (pathCSV != null) {
        String[] splitData = pathCSV.split("\\s*,\\s*");
        for (int i = 0; i < splitData.length; i++) {
            if (!(splitData[i] == null) || !(splitData[i].length() == 0)) {
                result.add(splitData[i].trim());
            }
        }
    }

    return result;
}

CSV文件看起来像:

1.0  8.0  4.0  6.0
3.0  2.0  1.0  5.0
7.0  1.0  8.0  1.0
1.0  2.0  1.0  4.0

请注意,没有标题。该文件以无标题的值开头。我收到的错误是:

Exception in thread "main" java.lang.NumberFormatException: For input string: ""1.0""
    at sun.misc.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:2043)
    at sun.misc.FloatingDecimal.parseDouble(FloatingDecimal.java:110)
    at java.lang.Double.parseDouble(Double.java:538)
    at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
    at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1382)
    at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:482)
    at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:472)
    at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708)
    at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
    at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:566)
    at Test4.trq(Test4.java:1063) \\ I mentioned that in the code above

您知道如何解决此问题吗?

java
3个回答
1
投票

替换

pathCSV.split("\\s*,\\s*");

with

pathCSV.split("\\s+");

这样数字就可以在空格上分开。目前,它们正以额外的"存储到结果中,例如""1.0""应该存储为"1.0"


0
投票

根据您看到的错误消息,该号码实际上被一对引号引起来,这很可能导致呼叫失败。

一种快速解决方案是使用asString = substring(1, asString.length() - 2);,其中asString是要解析为双精度型的字符串。


0
投票

返回前使用result.add(splitData[i].trim(). replaceAll("/"","") )

© www.soinside.com 2019 - 2024. All rights reserved.