Accessing an array inside a JS object and removing an item from it by index

问题

Let's say I have an object where the values are arrays, like this:

{
  123456: ['apple','orange','banana'],
  987654: ['dog','cat','mouse'],
  112233: ['car','truck','bike']
}

and that I have access to 2 variables, itemID that has the key assigned to it, and the array index of the item I want to remove. For example

itemID = 987654;
n = 1;

So the resulting object I want to get would be

{
  123456: ['apple','orange','banana'],
  987654: ['dog','mouse'],
  112233: ['car','truck','bike']
}

I need to write a function

removeItem(itemID, n) {
}

What would be the best way to do it?

回答1:

Here is the solution

var obj = {
  123456: ['apple','orange','banana'],
  987654: ['dog','cat','mouse'],
  112233: ['car','truck','bike']
}


function removeItem(itemID, n) {
 if(!obj[itemID]) {
  return;
 }
 obj[itemID].splice(n, 1);
}

removeItem(987654, 1);
console.log(obj);

I'll add some explanation, To access object by key you : obj[key];

Array.splice in this case, meaning(splice(n, 1)) - take the item at index n and remove exactly one item from that index;

One more note : when you access object the key should be a string So I'l change removeItem(987654, 1); To: removeItem('987654', 1);

It will work in both ways thow.

回答2:

It can be done using splice method:

const removeItem = (itemID, n) => {
    if (!foo[itemID])
        return;
    foo[itemID].splice(n,1);
    return foo;
}

An example:

var foo = {
  123456: ['apple','orange','banana'],
  987654: ['dog','cat','mouse'],
  112233: ['car','truck','bike']
};


const removeItem = (itemID, n) => {
    if (!foo[itemID])
        return;
    foo[itemID].splice(n, 1);
    return foo;
}

console.log(removeItem(987654, 1));

回答3:

var obj = /*ur obj*/
var itemID = 987654;
var n = 1;

removeItem(itemID, n) {
  let str = obj[itemID][n];
  this.obj[itemID] = obj[itemID].filter(item => item != str);
}

回答4:

Try this:

<!DOCTYPE html>
<html>
<body onload="removeItem(987654,1)">

<p id="demo"></p>

<script>
var data ={
  123456: ['apple','orange','banana'],
  987654: ['dog','cat','mouse'],
  112233: ['car','truck','bike']
};
function removeItem(itemID, n) {
  data[itemID] =  data[itemID].filter(function(value, index, array) {
   return index != n;
  });
  document.getElementById("demo").innerHTML = JSON.stringify(data);
}
</script>

</body>
</html>

来源：https://stackoverflow.com/questions/59477367/accessing-an-array-inside-a-js-object-and-removing-an-item-from-it-by-index

标签

javascript

arrays

object