从数组中删除不匹配的元素

Question

So, I have two arrays and I want to remove all elements from array2 that's not included as a number in array1 (example arrays below will make it more clear).

I guess a for loop and an if statement could do the trick, but I assume there's a more elegant solution for this, if someone has a suggestion?

var elemsToKeep = [1, 3, 5, 6, 8];

var arr[0] = 'foo1';
var arr[1] = 'foo2';    // remove
var arr[2] = 'foo3';
var arr[3] = 'foo4';    // remove
var arr[4] = 'foo5';
var arr[5] = 'foo6';
var arr[6] = 'foo7';    // remove
var arr[7] = 'foo8';
var arr[8] = 'foo9';    // remove
var arr[9] = 'foo10';   // remove

Answer 1

Instead of trying to remove the values you don't need, rather create a new array with only the values you need. Hint: it involves a loop and Array.push .

Answer 2

Perhaps a filter (first time I use one so I just popped off and made a jsfiddle.net )

Note updated to remove any non-numeric char - that means 1foo2 will become 12 - let me know if that is not what you want, then a different regexp can be applied

var elemsToKeep = [1, 3, 5, 6, 8];

var arr=[];
arr[0] = 'one1';
arr[1] = 'two2';   // remove
arr[2] = 'three3';
arr[3] = 'four4';  // remove
arr[4] = 'five5';
arr[5] = 'six6';
arr[6] = 'seven7'; // remove
arr[7] = 'eight8';
arr[8] = 'nine9';  // remove
arr[9] = 'ten0';   // remove

function keep(element, index, array) {
  var num = parseInt(element.replace(/[^\d]/g,''),10); // any char!
  return elemsToKeep.indexOf(num) !=-1;
}

var filtered = arr.filter(keep);
alert(filtered)​

Answer 3

You could use Underscore's _reject function:

var filtered = _reject(arr2, function(element, index) {
   return elementsToKeep.indexOf(index +1) == -1;
});