使用ID和Javascript从数组中删除项目

Question

I have a function like this: pickListSelect array is has all id (numbers) to delete objects in source array , and target array it is to push elements deleted from source array .

    function copy(pickListSelect, source, target) {

         var i, id;

         for (i = 0; i < pickListSelect.length; i++) {
              id = pickListSelect[i];              
              source.splice(id,1);
         }
         pickListSelect = [];
   }

So what I need is delete specific object from source arra y. I tried with that code but for example if I need to delete object with id=5, it only deleted item 5 from the list.

The structure of source array is this:

    [Object, Object, Object, Object, Object, Object, Object, Object, Object]
    0:Object
    plantId:1
    plantName:"Plant 1"

...the rest of others are similar object

Answer 1

You need to find plant in your source by plantId first, and then delete it from original array and push to target. Open console and it should log deleted plants:

 var plants = [ { plantId: 1, plantName: 'plant 1' }, { plantId: 2, plantName: 'plant 2' }, { plantId: 3, plantName: 'plant 3' }, { plantId: 4, plantName: 'plant 4' } ]; function copy(pickListSelect, source, target) { var i, id, el; for (i = 0; i < pickListSelect.length; i++) { id = pickListSelect[i]; el = findPlant(source, id); source.splice(source.indexOf(el), 1); target.push(el); } } function findPlant (arr, id) { return arr.filter(function (plant) { return plant.plantId == id })[0] } var test = []; copy([2,3], plants, test); console.log(test); 

Answer 2

When you use .splice you need to pass in the start index at which to splice and the amount of items to splice, try this:

source.splice(i,1); // i is your starting index here


array.splice(start, deleteCount[, item1[, item2[, ...]]])

MDN on .splice

Now in your actual code you need to check to see if the id matches and then splice using the above code:

function copy(pickListSelect, source, target) {

     var i, id;

     for (i = 0; i < pickListSelect.length; i++) {
          if (pickListSelect[i].id === someId) {              
            source.splice(i,1);
          }
     }
     pickListSelect = [];
 }

Answer 3

You're not looking up the index of the source array with a matching id. It might be better to do something like this.

var idsToRemove = {};

// build an object of ids to remove (effectively a hashset)
for (var i = 0; i < pickSelectList.length; i++) {
    idsToRemove[pickSelectList[i]] = true;
}

// loop through the source array to find any objects with ids to remove
for (var j = 0; j < source.length; j++) {
    if (source[j].plantId in idsToRemove) {
        target.push(source.splice(j, 1));
    }
}

Answer 4

You can take a look at this fiddler here . I have used underscore.js to find the correct element from source and move it to the target array.

var copy = function(pickListSelect, source, target) {
    for (i = 0; i < pickListSelect.length; i++) {
      id = pickListSelect[i];
      var deleteIndex = _.findIndex(source, {Id: id});
            var deletedItem = source.splice(deleteIndex, 1);
            target.push(deletedItem[0])
    }
        pickListSelect = [];
    return target;
  }