如何在多值hashmap中值搜索为true时打印键？

pdkcd3nj 于 2021-07-06 发布在 Java

关注(0)|答案(1)|浏览(217)

所以我最近创建的程序，hashmap中有多个值，下面是程序：

studentID.put("P2530001", "P2530230" + "P2534141");
    studentID.put("P2531120", "P2530201");
    String SearchValue = sc.nextLine();
    boolean found = studentID.values().stream().anyMatch(value -> value.contains(SearchValue));

    if (found == true) {
        System.out.println("The P number that you entered is: " + SearchValue);
        System.out.println("P number exist, here is the assigned mentor:");
        System.out.println();// print the key when passed value search
    } else {
        System.out.println("The P number that you entered is: " + SearchValue);
        System.out.println("P number does not exist!");
    }

我尝试使用studentid.contains.values（searchvalue）；，但它不起作用，谁能帮我，告诉我我应该把什么程序，谢谢。

Java data-structures

来源：https://stackoverflow.com/questions/64914364/how-to-print-the-key-while-value-search-is-true-in-multi-values-hashmap

1条答案

按热度按时间

6jjcrrmo1#

您可以使用以下代码：

Optional<Map.Entry<String, String>>
        result = studentID.entrySet().stream().filter(e -> e.getValue().contains(SearchValue)).findFirst();

    if (result.isPresent()) {
        System.out.println("The P number that you entered is: " + SearchValue);
        System.out.println("P number exist, here is the assigned mentor:");
        System.out.println(result.get().getKey());// print the key when passed value search
    } else {
        System.out.println("The P number that you entered is: " + SearchValue);
        System.out.println("P number does not exist!");
    }

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如何在多值hashmap中值搜索为true时打印键？

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