Question 313100 in Json Question posted in
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Json – How to compare two ArrayList and output value

Without using GSON.

I’m attempting to pull the text value from the ‘chores’ array if there is a matching value in ‘chore’ array within myFilterObj object.

{
    "chores": [
        {
            "text": "Wash the car",
            "value": 1
        },
        {
            "text": "Mow the lawn",
            "value": 2
        },
        {
            "text": "Vaccumm the floor",
            "value": 3
        },
        {
            "text": "Walk the dog",
            "value": 4
        }
    ],
    "myFilterObj": {
        "chore": [
            1,
            2
        ]
    }
}

The first thing I did was convert them to ArrayLists.

Below are the two ArrayLists. My goal is to printout the text from first ArrayList if that value is in the second ArrayList.

For Example: Wash the car and Vaccumm the floor should printout since 1 and 2 are in the second ArrayList and 1 and 2 are values in the first ArrayList.

Here is what I have so far. I’m stuck on trying to do the comparison for allChores.value to value. I think I should be using removeAll or contains??

JSONArray allChores = data.getJSONArray("chores");
JSONArray myChores = myFilterObj.getJSONArray("chore"); 
ArrayList<Object> listdata1 = new ArrayList<Object>();
ArrayList<Object> listdata2 = new ArrayList<Object>();
if (allChores != null) {
    for (int i = 0; i < allChores.length(); i++) {
        //Adding each element of JSON array into ArrayList
        listdata1.add(allChores.get(i));
    }
}
if (myChores != null) {
    for (int i = 0; i < myChores.length(); i++) {
        //Adding each element of JSON array into ArrayList
        listdata2.add(myChores.get(i));
    }
}
//comapare allChores.value to myChores(value)
//printout allChores.text on match 

[ 
    {
        "text":"Wash the car",
        "value":1
    }, 
    {
        "text":"Mow the lawn",
        "value":7
    }, 
    {
        "text":"Vaccumm the floor",
        "value":2
    }, 
    {
        "text":"Walk the dog",
        "value":8
    }
]
[
    1,
    2,
    3
]
Tags:

2

Answers


  1. 0

    You could use the .filter method to achieve this:

    choresArray.filter((chore) => choreIdArray.includes(chore.value))

    which would return a list of the chores that are in your array,

    then if you just want the label you can use .map

    results.map(res => res.label)

    which will return a string array.

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  2. 0

    You didn’t answer Abra’s question about whether you use GSON or not, but I’ll assume you do use GSON and adapt the answer when it turns out that you don’t.

    I would start by converting the input into POJOs. For that I would introduce for every object in the input a separate record Chore, McChores and Input itself.

    record Chore(int value, String text) {
}

record MyChores(List<Integer> chore) {
}

record Input(List<Chore> chores, MyChores myFilterObj) {
}

    Such that you can then create look up map of the chores

    public static void main(String[] args) {
    final var data = """
            {
                "chores": [
                    {
                        "text": "Wash the car",
                        "value": 1
                    },
                    {
                        "text": "Mow the lawn",
                        "value": 2
                    },
                    {
                        "text": "Vaccumm the floor",
                        "value": 3
                    },
                    {
                        "text": "Walk the dog",
                        "value": 4
                    }
                ],
                "myFilterObj": {
                    "chore": [
                        1,
                        2,
                        7
                    ]
                }
            }
            """;
    final var input = new Gson().fromJson(data, Input.class);
    final Map<Integer, String> choresLookup = input.chores().stream()
            .collect(Collectors.toMap(Chore::value, Chore::text));
    final var myChores = input.myFilterObj().chore().stream()
            .filter(choresLookup::containsKey) // absent values gets filtered out
            .map(choresLookup::get)
            .toList();
}

    Results in

    [Wash the car, Mow the lawn]
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