javascript - 在条件下删除数组元素 [英] javascript - remove array element on condition
问题描述
我想知道如何在javascript中实现一个方法,删除清除某个条件的数组的所有元素。 (最好不使用jQuery)
I was wondering how I'd go about implementing a method in javascript that removes all elements of an array that clear a certain condition. (Preferably without using jQuery)
前。
ar = [ 1, 2, 3, 4 ];
ar.removeIf( function(item, idx) {
return item > 3;
});
以上内容将遍历数组中的每个项目并删除所有对于条件返回true
(在示例中,item> 3)。
The above would go through each item in the array and remove all those that return true
for the condition (in the example, item > 3).
我刚开始使用javascript并且想知道是否有人知道一种简短有效的方法来完成这项工作。
I'm just starting out in javascript and was wondering if anyone knew of a short efficient way to get this done.
- 更新 -
如果条件也适用于对象属性也会很棒。
It would also be great if the condition could work on object properties as well.
Ex。
ar = [ {num:1, str:"a"}, {num:2, str:"b"}, {num:3, str:"c"} ];
ar.removeIf( function(item, idx) {
return item.str == "c";
});
如果 item.str ==c,该项目将被删除
- update2 -
它如果指数条件也可以有效,那就太好了。
It would be nice if index conditions could work as well.
前。
ar = [ {num:1, str:"a"}, {num:2, str:"b"}, {num:3, str:"c"} ];
ar.removeIf( function(item, idx) {
return idx == 2;
});
推荐答案
您可以将自己的方法添加到数组
做类似的事情,如果 filter
不适合你。
You could add your own method to Array
that does something similar, if filter
does not work for you.
Array.prototype.removeIf = function(callback) {
var i = 0;
while (i < this.length) {
if (callback(this[i], i)) {
this.splice(i, 1);
}
else {
++i;
}
}
};
对我而言,这是JavaScript最酷的功能之一。伊恩指出了一种更有效的方法来做同样的事情。考虑到它是JavaScript,每一点都有帮助:
To me, that's one of the coolest features of JavaScript. Ian pointed out a more efficient way to do the same thing. Considering that it's JavaScript, every bit helps:
Array.prototype.removeIf = function(callback) {
var i = this.length;
while (i--) {
if (callback(this[i], i)) {
this.splice(i, 1);
}
}
};
这避免了甚至担心更新长度
或抓住下一个项目,因为你的工作方式是向左而不是正确。
This avoids the need to even worry about the updating length
or catching the next item, as you work your way left rather than right.
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