How to get the number of elements for elements that satisfy a condition-CodePudding

I'm having a problem. I have an array as shown below:

0: {type: 'Text', id_a: '123789', value: 'The fifth chapter of the World Première Ducati will be held at the Expo Dubai on December 9th.', number: 2, id: 7}
1: {type: 'Image', id_a: '123789', value: 'b_desertx-dwp2022-2-uc336332-high.jpg', number: 3, id: 8}
2: {type: 'Video youtube', id_a: '123789', value: 'https://youtu.be/SnuyDoXxC4g', number: 5, id: 10}
3: {type: 'Image', id_a: '123456', value: 'moto_guzzi_v100_mandello.jpg', number: 3, id: 3}
4: {type: 'Text', id_a: '123456', value: 'The star of the Piaggio group stand is without doubt ... Discover all his secrets with our video', number: 2, id: 2}

Of these I want, for example, to take those that have an id_a equal to 123456 and have me return the value (therefore, referring to id_a = 123456 it must return the two relative arrays) then

3: {type: 'Image', id_a: '123456', value: 'moto_guzzi_v100_mandello.jpg', number: 3, id: 3}
4: {type: 'Text', id_a: '123456', value: 'The star of the Piaggio group stand is without doubt ... Discover all his secrets with our video', number: 2, id: 2}

Except I get this below

{type: 'Image', id_a: '123456', value: 'moto_guzzi_v100_mandello.jpg', number: 3, id: 3}
{type: 'Text', id_a: '123456', value: 'The star of the Piaggio group stand is without doubt ... Discover all her secrets with our video', number: 2, id: 2}

without the numbering in order to be able to retrieve the value (therefore using the value attribute) of each of them.

How can I do this?

   var myArr = JSON.parse(this.responseText);
   for(var i = 0, len = myArr.Items.length; i < len; i  ){           
        var id_art = myArr.Items[i].id_a;
        if(id_art == 123456) {
            myArr.Items[i];
            console.log(myArr.Items[i]);
   }

myArr is:

{Items: Array (5), Count: 5, ScannedCount: 5}
Count: 5
Items: Array (5)
0: {type: 'Text', id_a: '123789', value: 'The fifth chapter of the Ducati World Première will take place at the Expo Dubai on December 9th.', Number: 2, id: 7}
1: {type: 'Image', id_a: '123789', value: 'b_desertx-dwp2022-2-uc336332-high.jpg', number: 3, id: 8}
2: {type: 'Video youtube', id_a: '123789', value: 'https://youtu.be/SnuyDoXxC4g', number: 5, id: 10}
3: {type: 'Image', id_a: '123456', value: 'moto_guzzi_v100_mandello.jpg', number: 3, id: 3}
4: {type: 'Text', id_a: '123456', value: 'The star of the Piaggio group stand is without doubt ... Discover all her secrets with our video', number: 2, id: 2}
length: 5

WHILE

    var x=0;
    while(x <= Object.keys(results).length){
        if(Object.keys(results[x])=="Image")
          console.log(results[x].value);
    }

CodePudding user response：

So based on the edit the array with actual information we want is the value of the Items key.

myArr doesn't seem to be an array, but it's actually a key-value pair based on the edit as well.

Here is my attempt:

var myArr = JSON.parse(this.responseText);

//console.log(myArr.Items)
//Declare and initialize k-v pair.
var results = {};
for (var i = 0, len = myArr.Items.length; i < len; i  ) {
    var id_art = myArr.Items[i].id_a;
    if (id_art == 123456) {
        //console.log(i, myArr.Items[i]);
        //Create the key-value pair and store the index information in the key.
        results[i] = myArr.Items[i];
    }
}

console.log(results);

Output:

{
  '3': {
    type: 'Image',
    id_a: '123456',
    value: 'moto_guzzi_v100_mandello.jpg',
    number: 3,
    id: 3
  },
  '4': {
    type: 'Text',
    id_a: '123456',
    value: 'The star of the Piaggio group stand is without doubt ... Discover all his secrets with our video',
    number: 2,
    id: 2
  }
}

Explanation: Since you have specified you do not care how the data is stored. I have put it in the key of a new key-value Object in Javascript (do they call these dictionaries or hashmaps here?).

Thus, you can access them now by cycling through the elements in the dictionary, or getting a list of just keys in the dictionary and choosing which value you would like to access.

For instance, to print out a list of keys that exist in this object, you might use:

for (let value of Object.keys(results)) {
    console.log(value)
}

Let me know if I have understood you correctly.

Edit

To get the output mentioned in your comment, now using while:

var x = 0;
while (x < Object.entries(results).length) {
    //console.log(Object.entries(results)[x][1]);
    if (Object.entries(results)[x][1].type == "Image"){
        console.log("The index is: ", Object.entries(results)[x][0]);
        console.log("The value is: ", Object.entries(results)[x][1].value);
    }
    x  ;

}

Output: