Javascript 如何用Javascript替换数组中的项目？
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How to replace an item in an array with Javascript?
提问by James
Each item of this array is some number.
这个数组的每一项都是一些数字。
var items = Array(523,3452,334,31, ...5346);
How do I replace some number in with array with a new one?
如何用新的数组替换数组中的某些数字？
For example, we want to replace 3452 with 1010, how would we do this?
比如我们想把3452换成1010，怎么做呢？
回答by Eli
var index = items.indexOf(3452);
if (index !== -1) {
items[index] = 1010;
}
Also it is recommend you not use the constructor method to initialize your arrays. Instead, use the literal syntax:
此外，建议您不要使用构造函数方法来初始化数组。相反，使用文字语法：
var items = [523, 3452, 334, 31, 5346];
You can also use the ~operator if you are into terse JavaScript and want to shorten the -1comparison:
~如果您喜欢简洁的 JavaScript 并想缩短-1比较，您也可以使用运算符：
var index = items.indexOf(3452);
if (~index) {
items[index] = 1010;
}
Sometimes I even like to write a containsfunction to abstract this check and make it easier to understand what's going on. What's awesome is this works on arrays and strings both:
有时我什至喜欢写一个contains函数来抽象这个检查，让我更容易理解发生了什么。很棒的是，这适用于数组和字符串：
var contains = function (haystack, needle) {
return !!~haystack.indexOf(needle);
};
// can be used like so now:
if (contains(items, 3452)) {
// do something else...
}
Starting with ES6/ES2015 for strings, and proposed for ES2016 for arrays, you can more easily determine if a source contains another value:
从用于字符串的 ES6/ES2015 开始，并为用于数组的 ES2016 提议，您可以更轻松地确定源是否包含另一个值：
if (haystack.includes(needle)) {
// do your thing
}
回答by gilly3
The Array.indexOf()method will replace the first instance. To get every instance use Array.map():
该Array.indexOf()方法将替换第一个实例。要获取每个实例，请使用Array.map()：
a = a.map(function(item) { return item == 3452 ? 1010 : item; });
Of course, that creates a new array. If you want to do it in place, use Array.forEach():
当然，这会创建一个新数组。如果您想就地进行，请使用Array.forEach()：
a.forEach(function(item, i) { if (item == 3452) a[i] = 1010; });
回答by Shimon Agassi
My suggested solution would be:
我建议的解决方案是：
items.splice(1, 1, 1010);
The splice operation will remove 1 item, starting at position 1 in the array (i.e. 3452), and will replace it with the new item 1010.
拼接操作将删除 1 个项目，从数组中的位置 1 开始（即3452），并将用新项目替换它1010。
回答by Tesserex
Use indexOf to find an element.
使用 indexOf 查找元素。
var i = items.indexOf(3452);
items[i] = 1010;
回答by mellamokb
Easily accomplished with a forloop.
用for循环轻松完成。
for (var i = 0; i < items.length; i++)
if (items[i] == 3452)
items[i] = 1010;
回答by VirtualTroll
You can edit any number of the list using indexes
您可以使用索引编辑任意数量的列表
for example :
例如 ：
items[0] = 5;
items[5] = 100;
回答by Yatrix
If using a complex object (or even a simple one) and you can use es6, Array.prototype.findIndexis a good one. For the OP's array, they could do,
如果使用复杂的对象（甚至是简单的对象）并且可以使用 es6，Array.prototype.findIndex则是一个不错的选择。对于 OP 的阵列，他们可以这样做，
const index = items.findIndex(x => x === 3452)
items[index] = 1010
For more complex objects, this really shines. For example,
对于更复杂的对象，这真的很闪耀。例如，
const index =
items.findIndex(
x => x.jerseyNumber === 9 && x.school === 'Ohio State'
)
items[index].lastName = 'Utah'
items[index].firstName = 'Johnny'
回答by Artee
Replacement can be done in one line:
替换可以在一行中完成：
var items = Array(523, 3452, 334, 31, 5346);
items[items.map((e, i) => [i, e]).filter(e => e[1] == 3452)[0][0]] = 1010
console.log(items);Or create a function to reuse:
或者创建一个函数来重用：
Array.prototype.replace = function(t, v) {
if (this.indexOf(t)!= -1)
this[this.map((e, i) => [i, e]).filter(e => e[1] == t)[0][0]] = v;
};
//Check
var items = Array(523, 3452, 334, 31, 5346);
items.replace(3452, 1010);
console.log(items);回答by AmerllicA
ES6way:
ES6方式：
const items = Array(523, 3452, 334, 31, ...5346);
We wanna replace 3452with 1010, solution:
我们想替换3452为1010，解决方案：
const newItems = items.map(item => item === 3452 ? 1010 : item);
Surely, the question is for many years ago and for now I just prefer to use immutablesolution, definitely, it is awesome for ReactJS.
当然，问题是多年前的问题，现在我更喜欢使用不可变的解决方案，当然，它对于ReactJS.
For frequent usage I offer below function:
对于经常使用，我提供以下功能：
const itemReplacer = (array, oldItem, newItem) =>
array.map(item => item === oldItem ? newItem : item);
回答by Goms
First method
第一种方法
Best way in just one line to replace or update item of array
在一行中替换或更新数组项的最佳方法
array.splice(array.indexOf(valueToReplace), 1, newValue)
Eg:
例如：
let items = ['JS', 'PHP', 'RUBY'];
let replacedItem = items.splice(items.indexOf('RUBY'), 1, 'PYTHON')
console.log(replacedItem) //['RUBY']
console.log(items) //['JS', 'PHP', 'PYTHON']
Second method
第二种方法
An other simple way to do the same operation is :
执行相同操作的另一种简单方法是：
items[items.indexOf(oldValue)] = newValue
