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我正在使用 Apache POI 3.9，我需要使用 Excel 公式 PERCENTILE 并从 Java 中评估公式。

问题是不支持 PERCENTILE。

我收到一个org.apache.poi.ss.formula.eval.NotImplementedException:错误

我有 3 种可能的解决方案来解决我的问题。

  1. 在 java 中编写我自己的百分位函数并将其贡献给 Apache POI 库（参见http://poi.apache.org/spreadsheet/eval-devguide.html）

  2. 将 Excel 工作表中的相关单元格放入 java 中，并使用诸如百分比计算中的函数进行计算

  3. 将 PERCENTILE 转换为 SMALL 函数，例如代替=PERCENTILE(A1:A10,95%) then=(SMALL(A1:A10,9)+SMALL(A1:A10,10))/2

在这个时间点，我需要一个快速的解决方案。对我来说，第三个将是最好的，但它并没有给出完全相同的结果。

在我退回到有点混乱的选项 2 之前，有没有人有任何想法？

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1 回答 1

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Thank you Gagravarr for your encouragement and also for your post Apache POI - How to register a function which was extremely helpful

I implemented the PERCENTILE function in the library in the following way:

  1. I downloaded the source code for Apache POI 3.9
  2. I checked for the ID number of the PERCENTILE function in src/resources/main/org/apache/poi/ss/formula/function/functionMetadata.txt (or online) and it was 328
  3. I thus added retval[328] = AggregateFunction.PERCENTILE; to the file org.apache.poi.ss.formula.eval.FunctionEval.java
  4. I added public static final Function PERCENTILE = new Percentile(); to the file org.apache.poi.ss.formula.functions.AggregateFunction.java in the appropriate place.

  5. I added to the same file the following code (which I based on the LargeSmall function; I had looked for the existing code/type of function which was most similar to what I wanted to do)

    private static final class Percentile extends Fixed2ArgFunction {

protected Percentile() {
}

public ValueEval evaluate(int srcRowIndex, int srcColumnIndex, ValueEval arg0,
        ValueEval arg1) {
    double dn;
    try {
        ValueEval ve1 = OperandResolver.getSingleValue(arg1, srcRowIndex, srcColumnIndex);
        dn = OperandResolver.coerceValueToDouble(ve1);
    } catch (EvaluationException e1) {
        // all errors in the second arg translate to #VALUE!
        return ErrorEval.VALUE_INVALID;
    }
    if (dn < 0 || dn > 1) { // has to be percentage
        return ErrorEval.NUM_ERROR;
    }

    double result;
    try {
        double[] ds = ValueCollector.collectValues(arg0);
        int N = ds.length;
        double n = (N - 1) * dn + 1;
        if (n == 1d) {
            result = StatsLib.kthSmallest(ds, 1);
        } else if (n == N) {
            result = StatsLib.kthLargest(ds, 1);
        } else {
            int k = (int) n;
            double d = n - k;
            result = StatsLib.kthSmallest(ds, k) + d
                    * (StatsLib.kthSmallest(ds, k + 1) - StatsLib.kthSmallest(ds, k));
        }

        NumericFunction.checkValue(result);
    } catch (EvaluationException e) {
        return e.getErrorEval();
    }

    return new NumberEval(result);
}

    }

  6. I then uploaded these two files individually and could then use the PERCENTILE function normally.

于 2013-10-29T17:37:28.180 回答