将带有return语句的for循环转换为stream和filter lambda语句[duplicate]

Question

如何将下面的for循环with return语句转换为lambda表达式或流with filter。

for(PhysicianData d : physicianDataList)
    {
        if(d.getPhysicianName().equals(physicianName))
        {
            return true;
        }
    }

Answer 1

使用它：

    class PhysicianData {
    String physicianName;

    public void setPhysicianName(final String physicianName) {
        this.physicianName = physicianName;
    }

    public String getPhysicianName() {
        return physicianName;
    }
}

@Test
void test() {
    PhysicianData one = new PhysicianData();
    one.setPhysicianName("A");
    PhysicianData two = new PhysicianData();
    two.setPhysicianName("B");
    List<PhysicianData> physicianDataList = List.of(one, two);
    assertEquals(forMethod("A", physicianDataList), streamMethode("A", physicianDataList));
}

private boolean forMethod(final String physicianName, final List<PhysicianData> physicianDataList) {
    for (PhysicianData d : physicianDataList) {
        if (d.getPhysicianName().equals(physicianName)) {
            return true;
        }
    }
    return false;
}

private boolean streamMethode(final String physicianName, final List<PhysicianData> physicianDataList) {
    return physicianDataList.stream().anyMatch(x-> x.getPhysicianName().equals(physicianName));
}

Answer 2

由于您正在寻找与名称相等检查匹配的任何内容（任何操作词），我建议查看Stream::anyMatch（）方法，以及它的其他对应的Stream::allMatch（）和Stream::noneMatch（）。上面的代码可以重写为：

boolean result = physicianDataList
    .stream()
    .anyMatch(physicianData -> physicianData.getPhysicianName().equals(physicianName);

Answer 3

使用anyMatch（）

boolean result = physicianDataList.stream()
            .map(PhysicianData::getPhysicianName) // Stream of names
            .filter(Objects::nonNull) //Skip nulls
            .anyMatch(name -> name.equals(physicianName));