Removing sections from an array

Question

I have the following array:

KHWArray = [{"date":"23 Jan 14","hours":12,"mins":"31","score":22},
           {"date":"23 Jan 14","hours":12,"mins":"36","score":22},
           {"date":"23 Jan 14","hours":12,"mins":"44","score":22}
           ]

How can I go about deleting the hours and mins sections from all arrays so I am just left with date and score.

I have looked into splicing and delete but can't seem to make this work

Have a look here: http://stackoverflow.com/questions/7015512/removing-an-element-from-an-array-specifying-a-value-in-javascript?rq=1 — ChrisSwires, Jan 24 '14 at 10:36

score 3 · Accepted Answer · answered Jan 24 '14 at 10:38

3

Your array elements are objects, not arrays and there's no built-in function to slice objects. It's easy to write though:

function removeKeys(obj, keys) {
    keys.forEach(function(key) { delete obj[key] });
    return obj
}

and then

KHWArray = KHWArray.map(function(elem) {
    return removeKeys(elem, ['hours', 'mins'])    
})

http://jsfiddle.net/HZDaX/

answered Jan 24 '14 at 10:38

georg

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Note: The `map` method does not exist in older browsers, for example IE8. – Guffa Jan 24 '14 at 10:55

roland · Answer 2 · 2014-01-24T10:43:45.687

map seems your best bet:

var result = KHWArray.map(function(elt) {
  return {date: elt.date, score: elt.score};
});

As an alternative use the versatile reduce:

var result = KHWArray.reduce(function(target, elt) {
  target.push({date: elt.date, score: elt.score});
  return target;
}, []);

Basically pass an empty array as the second argument; it will be referenced as target inside the handler. Push an object that fits your needs and return your target.

Caution: map and reduce are both part of the ECMAScript 5th edition. Ensure your targeted browsers support it (or provide a shim).

score 2 · Answer 3 · answered Jan 24 '14 at 10:45

2

Use the delete operator to delete properties from an object:

for (var i = 0; i < KHWArray.length; i++) {
  delete KHWArray[i].hours;
  delete KHWArray[i].mins;
}

answered Jan 24 '14 at 10:45

Guffa

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Removing sections from an array

3 Answers3