I'm getting LinkedHashMap grades = courses.get(choise).getGrades();
I need to save the grades values in an array/arraylist.
I'm able to get values and keys in loop
String key = "";
String value = "";
for (Object o : grades.keySet()){
key = o.toString();
value = grades.get(o).toString();
}
And print it like so
System.out.println("Grades: " + value);
Example output is
Grades:[0, 3, 2, 5, 3]
My goal is to have each grade separated in an array/list.
You don't have to worry about the order. Whether you obtain the values() or keySet() or entrySet() from the LinkedHashMap, the iteration order of any of them would be according to the insertion order into the LinkedHashMap.
Putting the values in a List is as simple as:
List<SomeType> grades = new ArrayList<>(grades.values());
Of course, for that to work you have to change LinkedHashMap grades to LinkedHashMap grades<KeyType,SomeType>.
private LinkedHashMap<Student, ArrayList<Integer>> grades; It's to store student grades, so it contains Student object and grades as ArrayList, that he have.The first thing you have to sort out, is the raw type:
LinkedHashMap grades = courses.get(choise).getGrades();
You need the generic type on the variable type, even if you just use ?:
LinkedHashMap<?, ?> grades = courses.get(choise).getGrades();
but if you know a more specific type than ?, you can use that - it looks from the question like your keys at least are Strings.
Then:
List<String> list =
grades.values().stream()
.map(Object::toString)
.collect(Collectors.toList());
Found solution from a website.
The below codes does the trick if provided that grades is a LinkedHashMap<String, String>.
String[] arrayGrades = grades.keySet().toArray(new String[0]);
The code was tested wthin JavaVersion.VERSION_1_8 environment.
list.add(value)on the list? or not?grades.entrySet()if you want both key and value together, orgrades.values()if you just want the values.LinkedHashMap.