从Javascript中的数组中删除空元素(Remove empty elements from an array in Javascript)

从Javascript中的数组中删除空元素(Remove empty elements from an array in Javascript)

如何从JavaScript中的数组中删除空元素？

有一个直截了当的方法，还是需要循环并手动删除？

How do I remove empty elements from an array in JavaScript?

Is there a straightforward way, or do I need to loop through it and remove them manually?

最满意答案

我使用这种方法，扩展了本机Array原型：

Array.prototype.clean = function(deleteValue) { for (var i = 0; i < this.length; i++) { if (this[i] == deleteValue) { this.splice(i, 1); i--; } } return this; }; test = new Array("", "One", "Two", "", "Three", "", "Four").clean(""); test2 = [1, 2,, 3,, 3,,,,,, 4,, 4,, 5,, 6,,,,]; test2.clean(undefined);

或者您可以简单地将现有元素推入其他数组：

// Will remove all falsy values: undefined, null, 0, false, NaN and "" (empty string) function cleanArray(actual) { var newArray = new Array(); for (var i = 0; i < actual.length; i++) { if (actual[i]) { newArray.push(actual[i]); } } return newArray; } cleanArray([1, 2,, 3,, 3,,,,,, 4,, 4,, 5,, 6,,,,]);

EDIT: This question was answered almost 9 year ago, when there were not much useful built-in methods in the Array.prototype.

Now, certainly I would just recommend you to use the filter method.

Take in mind that this method will return you a new array with the elements that pass the criteria of the callback function you provide to it, for example, if you want to remove null or undefined values:

var array = [0, 1, null, 2, "", 3, undefined, 3,,,,,, 4,, 4,, 5,, 6,,,,];

var filtered = array.filter(function (el) {
  return el != null;
});

console.log(filtered); 
  
 
 
It will depend on what you consider to be "empty", for example if you were dealing with strings, the above function wouldn't remove elements that are an empty string.
 
One common pattern that I see often used is to remove elements that are falsy, which include an empty string "", 0, NaN, null, undefined, and false.
 
You can simply pass to the filter method, the Boolean constructor function, or simply return the same element in the filter criteria function, for example:
 
var filtered = array.filter(Boolean);
 
Or
 
var filtered = array.filter(function(el) { return el; });
 
In both ways this works because the filter method in the first case, calls the Boolean constructor as a function, converting the value, and in the second case, the filter method internally converts the return value of the callback implicitly to Boolean.
 
If you are working with sparse arrays, and you are trying to get rid of the "holes", you can simply use the filter method passing a callback that returns true, for example:
 
 
 
  
  
var sparseArray = [0, , , 1, , , , , 2, , , , 3],
    cleanArray = sparseArray.filter(function () { return true });

console.log(cleanArray); // [ 0, 1, 2, 3 ] 
  
 
 
Old answer: Don't do this!
 
I use this method, extending the native Array prototype:
 
Array.prototype.clean = function(deleteValue) {
  for (var i = 0; i < this.length; i++) {
    if (this[i] == deleteValue) {         
      this.splice(i, 1);
      i--;
    }
  }
  return this;
};

test = new Array("", "One", "Two", "", "Three", "", "Four").clean("");
test2 = [1, 2,, 3,, 3,,,,,, 4,, 4,, 5,, 6,,,,];
test2.clean(undefined);
 
Or you can simply push the existing elements into other array:
 
// Will remove all falsy values: undefined, null, 0, false, NaN and "" (empty string)
function cleanArray(actual) {
  var newArray = new Array();
  for (var i = 0; i < actual.length; i++) {
    if (actual[i]) {
      newArray.push(actual[i]);
    }
  }
  return newArray;
}

cleanArray([1, 2,, 3,, 3,,,,,, 4,, 4,, 5,, 6,,,,]);