How to get minimum and maximum value from List of

问题:

I have class like:

public class Test {
    private String Fname;
    private String Lname;
    private String Age;
    // getters, setters, constructor, toString, equals, hashCode, and so on
}

and a list like List<Test> testList filled with Test elements.

How can I get minimum and maximum value of age using Java 8?

回答1:

To simplify things you should probably make your age Integer or int instead of Sting, but since your question is about String age this answer will be based on String type.

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Assuming that String age holds String representing value in integer range you could simply map it to IntStream and use its IntSummaryStatistics like

IntSummaryStatistics summaryStatistics = testList.stream()
        .map(Test::getAge)
        .mapToInt(Integer::parseInt)
        .summaryStatistics();

int max = summaryStatistics.getMax();
int min = summaryStatistics.getMin();