如何在Java中声明和使用Python中的字典数组并对它们进行过滤？

Question

I'd like to understand how dictionaries work in Java,

I know that I can do something like

Map<String, String> map = new HashMap<String, String>();
map.put("dog", "type of animal");
System.out.`println`(map.get("dog"));

But I want to insert something that similar to what we do in python

T= []

value= {'name': 'someone', 'age': 13, 'tall': 1.55}

and I can add value to T, so I can filter them later by field ? Is this doable ?

UPDATE

In python, I add a list of dict to a list, to easily filter them.

T= []
a= {'name': 'someone', 'age': 13, 'tall': 1.55}
b= {'name': 'Jack', 'age': 14, 'tall': 1.39}

T.append(a)
T.append(b)

The result:

T= [ {'name': 'someone', 'age': 13, 'tall': 1.55}, {'name': 'Jack', 'age': 14, 'tall': 1.39}]

I would like to know what is the equivalent structure of these datastructure in python. How can I declare varibale like a, and b ?

filtered_T = [v for v in T if v['name'=='someone']] 

this will give

T= [ {'name': 'someone', 'age': 13, 'tall': 1.55}

Answer 1

In Java, you would typically create a class for this.

class Person {
    private final String name;
    private final int age;
    private final double height;

    //constructors, etc.
}

Then you would have a data-structure that holds the elements. A List<Person> could perfectly do the job here.

Person p1 = new Person("someone", 13, 1.55);
Person p2 = new Person("Jack", 14, 1.39);

List<Person> personsList = Arrays.asList(p1, p2);

The list comprehension you have to filter your elements would be written as (with Java 8):

personsList = personsList.stream()
                         .filter(p -> p.getName().equals("someone"))
                         .collect(Collectors.toList());

or

personsList.removeIf(p -> !p.getName().equals("someone"));

Basically, you get the stream from the original list, filter the person instances that have "someone" as their name, and collect the filtered elements into a list, that you assign back to the variable personsList .

The second approach removes the element in place in the list. Of course it only works if the implementation supports removal of elements.