假设我有以下代码:
var myArray = new Object();
myArray["firstname"] = "Bob";
myArray["lastname"] = "Smith";
myArray["age"] = 25;
现在如果我想要移除 "lastname" ,是否有类似于 myArray["lastname"].remove()
的等效方法呢?(我需要移除此元素,因为元素的数量很重要,我想保持数据干净)
假设我有以下代码:
var myArray = new Object();
myArray["firstname"] = "Bob";
myArray["lastname"] = "Smith";
myArray["age"] = 25;
现在如果我想要移除 "lastname" ,是否有类似于 myArray["lastname"].remove()
的等效方法呢?(我需要移除此元素,因为元素的数量很重要,我想保持数据干净)
你正在使用 Object,而且一开始并没有关联数组。如果使用关联数组,添加和删除项目的操作如下:
Array.prototype.contains = function(obj)
{
var i = this.length;
while (i--)
{
if (this[i] === obj)
{
return true;
}
}
return false;
}
Array.prototype.add = function(key, value)
{
if(this.contains(key))
this[key] = value;
else
{
this.push(key);
this[key] = value;
}
}
Array.prototype.remove = function(key)
{
for(var i = 0; i < this.length; ++i)
{
if(this[i] == key)
{
this.splice(i, 1);
return;
}
}
}
// Read a page's GET URL variables and return them as an associative array.
function getUrlVars()
{
var vars = [], hash;
var hashes = window.location.href.slice(window.location.href.indexOf('?') + 1).split('&');
for(var i = 0; i < hashes.length; i++)
{
hash = hashes[i].split('=');
vars.push(hash[0]);
vars[hash[0]] = hash[1];
}
return vars;
}
function ForwardAndHideVariables() {
var dictParameters = getUrlVars();
dictParameters.add("mno", "pqr");
dictParameters.add("mno", "stfu");
dictParameters.remove("mno");
for(var i = 0; i < dictParameters.length; i++)
{
var key = dictParameters[i];
var value = dictParameters[key];
alert(key + "=" + value);
}
// And now forward with HTTP-POST
aa_post_to_url("Default.aspx", dictParameters);
}
function aa_post_to_url(path, params, method) {
method = method || "post";
var form = document.createElement("form");
// Move the submit function to another variable
// so that it doesn't get written over if a parameter name is 'submit'
form._submit_function_ = form.submit;
form.setAttribute("method", method);
form.setAttribute("action", path);
for(var i = 0; i < params.length; i++)
{
var key = params[i];
var hiddenField = document.createElement("input");
hiddenField.setAttribute("type", "hidden");
hiddenField.setAttribute("name", key);
hiddenField.setAttribute("value", params[key]);
form.appendChild(hiddenField);
}
document.body.appendChild(form);
form._submit_function_(); // Call the renamed function
}
// To cut out one element via arr.splice(indexToRemove, numberToRemove);
array.splice(key, 1)
array.filter(function(n){return n});
不要尝试链接它们,因为splice返回已删除的元素;
你可以通过将条目显式地赋值为"undefined"来从地图中删除一个条目。就像在你的情况下:
myArray["lastname"] = undefined;
var removeItem = function (object, key, value) {
if (value == undefined)
return;
for (var i in object) {
if (object[i][key] == value) {
object.splice(i, 1);
}
}
};
var collection = [
{ id: "5f299a5d-7793-47be-a827-bca227dbef95", title: "one" },
{ id: "87353080-8f49-46b9-9281-162a41ddb8df", title: "two" },
{ id: "a1af832c-9028-4690-9793-d623ecc75a95", title: "three" }
];
removeItem(collection, "id", "87353080-8f49-46b9-9281-162a41ddb8df");
关于“数组”:
如果您知道索引:
array.splice(index, 1);
如果你知道值:
function removeItem(array, value) {
var index = array.indexOf(value);
if (index > -1) {
array.splice(index, 1);
}
return array;
}
delete
的最高投票答案在对象的情况下效果很好,但对于真正的数组则不然。如果我使用 delete
,它会从循环中删除元素,但将元素保留为空,并且数组的长度不会改变。这在某些情况下可能是个问题。
例如,如果我通过 delete
进行移除后,在 myArray 上执行 myArray.toString(),它会创建一个空条目,即 ,,
。
对我来说,唯一有效的方法是:
function removeItem (array, value) {
var i = 0;
while (i < array.length) {
if(array[i] === value) {
array.splice(i, 1);
} else {
++i;
}
}
return array;
}
使用方法:
var new = removeItem( ["apple","banana", "orange"], "apple");
// ---> ["banana", "orange"]
var myArray = newmyArray = new Object();
myArray["firstname"] = "Bob";
myArray["lastname"] = "Smith";
myArray["age"] = 25;
var s = JSON.stringify(myArray);
s.replace(/"lastname[^,}]+,/g, '');
newmyArray = JSON.parse(p);
不需要循环/迭代,我们可以得到相同的结果。