迭代HashMap <String, List<Class> &gt;

Question

how would i iterate over the list "values" that one string "key" has.

Map<String, List<wordsStreamed>> hm = new HashMap<String, List<wordsStreamed>>();
hm.put(wordChoosen, sw.streamMethod());

hm has one key and over 10,000 values. i want to iterate over the values so i can compare my key with all the values. also i would like to know if this code is the best way to get my String values from the list of classes.

hm.values().iterator().next().get(i).toString()

Answer 1

To iterate over your HashMap 's values, you can use fast-enumeration.

What you probably need here is to iterate over the key set, then access the List for each value and iterate over each of the List 's items to compare it to the key.

For instance:

Map<String, List<Object>> hm = new HashMap<String, List<Object>>();
for (String key : hm.keySet()) {
    // gets the value
    List<Object> value = hm.get(key);
    // checks for null value
    if (value != null) {
        // iterates over String elements of value
        for (Object element : value) {
            // checks for null 
            if (element != null) {
                // prints whether the key is equal to the String 
                // representation of that List's element
                System.out.println(key.equals(element.toString()));
            }
        }
    }
}

Note I've replaced your WordsStreamed class here with the Object class.

Answer 2

i want to iterate over the values so i can compare my key with all the value

looks like misuse of data structure , generally you should not have to iterate in such scenario and values should be mapped with key

you should enter the values those are logically mapped with keys so while retrieving you won't have to iterate through all they keys and associated values