java stream make map 经过两个不同的过滤器

Question

它应该return 一张地图。这个地图的键应该是字符串“transversion”和“transition”，地图的值应该是SNP对象的列表。 “转换”是 A<->G 和 C<->T 之间的变化，“转换”是 A<->C、G<->T、A<->T 和 C<->G 之间的变化。

两个滤镜应该怎么制作？

public class StreamAssignment {

    private static final List<Snp> SNP_COLLECTION = Snp.getSnpCollection();
    private static final String[] SNP_DATA = new String[14];

    static {
        SNP_DATA[0] = "100273;A;G;0.0123";
        SNP_DATA[1] = "100275;A;C;0.00323";
        SNP_DATA[2] = "117807;T;G;0.1915";
        SNP_DATA[3] = "162889;C;G;8.72E-4";
        SNP_DATA[4] = "190199;T;C;0.1019";
        SNP_DATA[5] = "277614;A;G;0.0168";
        SNP_DATA[6] = "372778;C;A;4.24E-5";
        SNP_DATA[7] = "417752;A;G;1.8474E-10";
        SNP_DATA[8] = "478808;A;G;1.535689E-8";
        SNP_DATA[9] = "556920;T;G;0.1097";
        SNP_DATA[10] = "676255;G;C;0.0016672";
        SNP_DATA[11] = "667280;A;G;0.00287";
        SNP_DATA[12] = "719876;C;A;0.006649";
        SNP_DATA[13] = "828771;A;C;0.097706";
    }

    public static Map<String, List<Snp>> getTransversionsTransitions() {
        Map<String, List<Snp>> result;
        result = SNP_COLLECTION.stream().filter();


        return null;
    }
}

snp class

package nl.bioinf.appdesign.d_streams_lambdas;

import java.util.ArrayList;
import java.util.List;

public class Snp {
    private final long position;
    private final char reference;
    private final char alternative;
    private final double minorAlleleFrequency;

    public Snp(long position, char reference, char alternative, double minorAlleleFrequency) {
        this.position = position;
        this.reference = reference;
        this.alternative = alternative;
        this.minorAlleleFrequency = minorAlleleFrequency;
    }

    public long getPosition() {
        return position;
    }

    public char getReference() {
        return reference;
    }

    public char getAlternative() {
        return alternative;
    }

    public double getMinorAlleleFrequency() {
        return minorAlleleFrequency;
    }

    @Override
    public String toString() {
        return "Snp{" +
                "position=" + position +
                ", reference=" + reference +
                ", alternative=" + alternative +
                ", minorAlleleFrequency=" + minorAlleleFrequency +
                '}';
    }

    public final static List<Snp> getSnpCollection() {
        List<Snp> snps = new ArrayList<>();
        snps.add(new Snp(100273, 'A', 'G', 0.0123));
        snps.add(new Snp(100275, 'A', 'C', 0.00323));
        snps.add(new Snp(117807, 'T', 'G', 0.1915));
        snps.add(new Snp(162889, 'C', 'G', 0.000872));
        snps.add(new Snp(190199, 'T', 'C', 0.1019));
        snps.add(new Snp(277614, 'A', 'G', 0.0168));
        snps.add(new Snp(372778, 'C', 'A', 0.0000424));
        snps.add(new Snp(417752, 'A', 'G', 1.8474e-10));
        snps.add(new Snp(478808, 'A', 'G', 1.535689e-8));
        snps.add(new Snp(556920, 'T', 'G', 0.1097));
        snps.add(new Snp(676255, 'G', 'C', 1.6672e-3));
        snps.add(new Snp(667280, 'A', 'G', 0.00287));
        snps.add(new Snp(719876, 'C', 'A', 0.006649));
        snps.add(new Snp(828771, 'A', 'C', 0.097706));
        return snps;
    }
}

Answer 1

由于您的 Snp class 不包含有关它是转换还是颠换的信息，因此您需要一个包装器 class。我会省略它，但它只需要有一个 String type 属性、Snp snp 属性和一个工厂方法（我们称之为解析）。

result = SNP_COLLECTION.stream()
        // do your filtering based on string values
        .map(SnpWrapper::parse) // String to Snp conversion
        // do your filtering based on Snp values
        .collect(Collectors.groupingBy(
                Wrapper::getType,
                Collectors.mapping(Wrapper::getSnp, Collectors.toList())
        ));

编辑：实际上不需要包装。您只需要提供一个实用方法。它可以放在 Snp 中，或者作为您当前 class 中的私有方法。让我们假设它是后者并且它被命名为 getSnpType:

result = SNP_COLLECTION.stream()
        // do your filtering based on string values
        .map(Snp::parse) // or whatever you have for String -> Snp
        // do your filtering based on Snp values
        .collect(Collectors.groupingBy(StreamAssignment::getSnpType));

Answer 2

在 re-examining 你的代码和阅读你的解释之后，我假设 Snp class 的属性 reference 和 alternative 是例如 A <-> C，其中 A 是参考，C 是备选。此外，您希望一组这些 Snp 实例用字符串“Transversions”标识，而另一个用“Transitions”标识。

这是我想出的代码。如果我误解了什么，请在评论中告诉我。

public static Map<String, List<Snp>> getTransversionsTransitions() {
    Map<String, List<Snp>> result = new HashMap<>();

    result.put("Transitions", SNP_COLLECTION.stream()
            .filter(snp -> (snp.getReference() == 'A' && snp.getAlternative() == 'G') || (snp.getReference() == 'C' && snp.getAlternative() == 'T'))
            .collect(Collectors.toList()));

    result.put("Transversions", SNP_COLLECTION.stream()
            .filter(snp -> (snp.getReference() == 'A' && snp.getAlternative() == 'C') || (snp.getReference() == 'G' && snp.getAlternative() == 'T')|| (snp.getReference() == 'C' && snp.getAlternative() == 'G'))
            .collect(Collectors.toList()));

    return result;
}

这只是检查输出是否符合您预期的主要步骤

public static void main(String[] args) {
    Map<String, List<Snp>> result = getTransversionsTransitions();
    for(String key: result.keySet()){
        System.out.printf("%s => %s%n", key, result.get(key));
    }
}

Answer 3

您可以将两个字符 reference 和 alternative 连接成一个字符串，然后使用正则表达式检查 transition 或 transversion。像

import java.util.function.BiFunction;

....


public static Map<String, List<Snp>> getTransversionsTransitions() {
    BiFunction<Character,Character,String> func =
            (a,b) -> (""+a+b).matches("AG|GA|CT|TC") ? "Transitions":"Transversions";
    return SNP_COLLECTION.stream()
            .collect(Collectors.groupingBy(snp -> func.apply(snp.getReference(),snp.getAlternative())));
}

java stream make map 经过两个不同的过滤器

java stream make map after two different filters

java

stream

java-stream