我有以下for循环，当我使用splice()删除一个项目时，我得到'seconds'是未定义的。我可以检查它是否未定义，但我觉得可能有一种更优雅的方式来做到这一点。他们的愿望是简单地删除一个项目，然后继续前进。
for (i = 0, len = Auction.auctions.length; i < len; i++) {
auction = Auction.auctions[i];
Auction.auctions[i]['seconds'] --;
if (auction.seconds < 0) {
Auction.auctions.splice(i, 1);
}
}
当前回答
这是一个很常见的问题。解决方案是反向循环:
for (var i = Auction.auctions.length - 1; i >= 0; i--) {
Auction.auctions[i].seconds--;
if (Auction.auctions[i].seconds < 0) {
Auction.auctions.splice(i, 1);
}
}
如果你把它们从末端取出来也没关系因为下标会在逆向过程中保留下来。
其他回答
删除参数
oldJson=[{firstName:'s1',lastName:'v1'},
{firstName:'s2',lastName:'v2'},
{firstName:'s3',lastName:'v3'}]
newJson = oldJson.map(({...ele}) => {
delete ele.firstName;
return ele;
})
它删除和创建新的数组，因为我们在每个对象上使用展开运算符，所以原始数组对象也不会受到损害
举两个例子:
一个例子
// Remove from Listing the Items Checked in Checkbox for Delete
let temp_products_images = store.state.c_products.products_images
if (temp_products_images != null) {
for (var l = temp_products_images.length; l--;) {
// 'mark' is the checkbox field
if (temp_products_images[l].mark == true) {
store.state.c_products.products_images.splice(l,1); // THIS WORKS
// this.$delete(store.state.c_products.products_images,l); // THIS ALSO WORKS
}
}
}
两个例子
// Remove from Listing the Items Checked in Checkbox for Delete
let temp_products_images = store.state.c_products.products_images
if (temp_products_images != null) {
let l = temp_products_images.length
while (l--)
{
// 'mark' is the checkbox field
if (temp_products_images[l].mark == true) {
store.state.c_products.products_images.splice(l,1); // THIS WORKS
// this.$delete(store.state.c_products.products_images,l); // THIS ALSO WORKS
}
}
}
这是一个很常见的问题。解决方案是反向循环:
for (var i = Auction.auctions.length - 1; i >= 0; i--) {
Auction.auctions[i].seconds--;
if (Auction.auctions[i].seconds < 0) {
Auction.auctions.splice(i, 1);
}
}
如果你把它们从末端取出来也没关系因为下标会在逆向过程中保留下来。
另一个简单的方法是一次消化数组元素:
while(Auction.auctions.length){
// From first to last...
var auction = Auction.auctions.shift();
// From last to first...
var auction = Auction.auctions.pop();
// Do stuff with auction
}
为什么在.splice上浪费CPU周期?该操作必须一次又一次地执行整个循环以删除数组中的一个元素。
为什么不只是在一个循环中使用传统的2个旗帜?
Const元素= [1,5,5,3,5,2,4]; Const remove = 5 I = 0 For(令j = 0;J < elements.length;j + +) { If(元素[j] !==删除){ 元素[i] =元素[j] 我+ + ｝ ｝ 元素。长度= I
