如何在 JavaScript 中将数组中的所有元素转换为整数？

How to convert all elements in an array to integer in JavaScript?

提问by Mohan Ram

I am getting an array after some manipulation. I need to convert all array values as integers.

经过一些操作，我得到了一个数组。我需要将所有数组值转换为整数。

My sample code

我的示例代码

var result_string = 'a,b,c,d|1,2,3,4';
result = result_string.split("|");
alpha = result[0];
count = result[1];
// console.log(alpha);
// console.log(count);
count_array = count.split(",");

count_arraynow contains 1,2,3,4but I need these value to be in integers.

count_array现在包含1,2,3,4但我需要这些值是整数。

I had used parseInt(count_array);, but it fails. JS considers each value in this array as string.

我曾经使用过parseInt(count_array);，但它失败了。JS 将此数组中的每个值视为字符串。

采纳答案by Nick Craver

You need to loop through and parse/convert the elements in your array, like this:

您需要遍历并解析/转换数组中的元素，如下所示：

var result_string = 'a,b,c,d|1,2,3,4',
    result = result_string.split("|"),
    alpha = result[0],
    count = result[1],
    count_array = count.split(",");
for(var i=0; i<count_array.length;i++) count_array[i] = +count_array[i];
//now count_array contains numbers

You can test it out here. If the +, is throwing, think of it as:

你可以在这里测试一下。如果+, 正在抛出，请将其视为：

for(var i=0; i<count_array.length;i++) count_array[i] = parseInt(count_array[i], 10);

回答by dheerosaur

ECMAScript5 provides a mapmethod for Arrays, applying a function to all elements of an array. Here is an example:

ECMAScript5map为Arrays提供了一种方法，将函数应用于数组的所有元素。下面是一个例子：

var a = ['1','2','3']
var result = a.map(function (x) { 
  return parseInt(x, 10); 
});

console.log(result);

For more information, check https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/map

有关更多信息，请查看https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/map

回答by Jonas Anseeuw

You can do

你可以做

var arrayOfNumbers = arrayOfStrings.map(Number);

• MDN Array.prototype.map

• MDN Array.prototype.map

For older browsers which do not support Array.map, you can use Underscore

对于旧的浏览器不支持Array.map，您可以使用下划线

var arrayOfNumbers = _.map(arrayOfStrings, Number);

回答by chzwzrd

var arr = ["1", "2", "3"];
arr = arr.map(Number);
console.log(arr); // [1, 2, 3]

回答by álvaro González

Just loop the array and convert items:

只需循环数组并转换项目：

for(var i=0, len=count_array.length; i<len; i++){
    count_array[i] = parseInt(count_array[i], 10);
}

Don't forget the second argument for parseInt.

不要忘记 parseInt 的第二个参数。

回答by ankhzet

The point against parseInt-approach:

反对parseInt-approach 的观点：

There's no need to use lambdas and/or give radixparameter to parseInt, just use parseFloator Numberinstead.

不需要使用 lambdas 和/或给radix参数给parseInt，只需使用parseFloat或Number代替。

---

---

Reasons:

原因：

1. It's working:

   var src = "1,2,5,4,3";
   var ids = src.split(',').map(parseFloat); // [1, 2, 5, 4, 3]
   
   var obj = {1: ..., 3: ..., 4: ..., 7: ...};
   var keys= Object.keys(obj); // ["1", "3", "4", "7"]
   var ids = keys.map(parseFloat); // [1, 3, 4, 7]
   
   var arr = ["1", 5, "7", 11];
   var ints= arr.map(parseFloat); // [1, 5, 7, 11]
   ints[1] === "5" // false
   ints[1] === 5   // true
   ints[2] === "7" // false
   ints[2] === 7   // true
   

2. It's shorter.

3. It's a tiny bit quickier and takes advantage of cache, when parseInt-approach - doesn't:

     // execution time measure function
     // keep it simple, yeah?
   > var f = (function (arr, c, n, m) {
         var i,t,m,s=n();
         for(i=0;i++<c;)t=arr.map(m);
         return n()-s
     }).bind(null, "2,4,6,8,0,9,7,5,3,1".split(','), 1000000, Date.now);
   
   > f(Number) // first launch, just warming-up cache
   > 3971 // nice =)
   
   > f(Number)
   > 3964 // still the same
   
   > f(function(e){return+e})
   > 5132 // yup, just little bit slower
   
   > f(function(e){return+e})
   > 5112 // second run... and ok.
   
   > f(parseFloat)
   > 3727 // little bit quicker than .map(Number)
   
   > f(parseFloat)
   > 3737 // all ok
   
   > f(function(e){return parseInt(e,10)})
   > 21852 // awww, how adorable...
   
   > f(function(e){return parseInt(e)})
   > 22928 // maybe, without '10'?.. nope.
   
   > f(function(e){return parseInt(e)})
   > 22769 // second run... and nothing changes.
   
   > f(Number)
   > 3873 // and again
   > f(parseFloat)
   > 3583 // and again
   > f(function(e){return+e})
   > 4967 // and again
   
   > f(function(e){return parseInt(e,10)})
   > 21649 // dammit 'parseInt'! >_<
   

1. 它正在工作：

   var src = "1,2,5,4,3";
   var ids = src.split(',').map(parseFloat); // [1, 2, 5, 4, 3]
   
   var obj = {1: ..., 3: ..., 4: ..., 7: ...};
   var keys= Object.keys(obj); // ["1", "3", "4", "7"]
   var ids = keys.map(parseFloat); // [1, 3, 4, 7]
   
   var arr = ["1", 5, "7", 11];
   var ints= arr.map(parseFloat); // [1, 5, 7, 11]
   ints[1] === "5" // false
   ints[1] === 5   // true
   ints[2] === "7" // false
   ints[2] === 7   // true
   

2. 它更短。

3. 当parseInt-approach - 不这样做时，它会更快一点并利用缓存：

     // execution time measure function
     // keep it simple, yeah?
   > var f = (function (arr, c, n, m) {
         var i,t,m,s=n();
         for(i=0;i++<c;)t=arr.map(m);
         return n()-s
     }).bind(null, "2,4,6,8,0,9,7,5,3,1".split(','), 1000000, Date.now);
   
   > f(Number) // first launch, just warming-up cache
   > 3971 // nice =)
   
   > f(Number)
   > 3964 // still the same
   
   > f(function(e){return+e})
   > 5132 // yup, just little bit slower
   
   > f(function(e){return+e})
   > 5112 // second run... and ok.
   
   > f(parseFloat)
   > 3727 // little bit quicker than .map(Number)
   
   > f(parseFloat)
   > 3737 // all ok
   
   > f(function(e){return parseInt(e,10)})
   > 21852 // awww, how adorable...
   
   > f(function(e){return parseInt(e)})
   > 22928 // maybe, without '10'?.. nope.
   
   > f(function(e){return parseInt(e)})
   > 22769 // second run... and nothing changes.
   
   > f(Number)
   > 3873 // and again
   > f(parseFloat)
   > 3583 // and again
   > f(function(e){return+e})
   > 4967 // and again
   
   > f(function(e){return parseInt(e,10)})
   > 21649 // dammit 'parseInt'! >_<
   

Notice: In Firefox parseIntworks about 4 times faster, but still slower than others. In total: +e< Number< parseFloat< parseInt

注意：在 Firefox 中的parseInt运行速度大约快 4 倍，但仍然比其他的慢。总计：+e< Number< parseFloat<parseInt

回答by Rithik Singh

var inp=readLine();//reading the input as one line string
var nums=inp.split(" ").map(Number);//making an array of numbers
console.log(nums);`

input : 1 9 0 65 5 7 output:[ 1, 9, 0, 65, 5, 7 ]

输入：1 9 0 65 5 7 输出：[ 1, 9, 0, 65, 5, 7 ]

what if we dont use .map(Number)

如果我们不使用怎么办 .map(Number)

code

代码

var inp=readLine();//reading the input as one line string
var nums=inp.split(" ");//making an array of strings
console.log(nums);

input : 1 9 0 65 5 7 output:[ '1', '9', '0', '65', '5', '7']

输入：1 9 0 65 5 7 输出：['1', '9', '0', '65', '5', '7']

回答by Juanma Menendez

If you want to convert an Array of digits to a single number just use:

如果要将数字数组转换为单个数字，请使用：

Number(arrayOfDigits.join(''));

Example

例子

const arrayOfDigits = [1,2,3,4,5];

const singleNumber = Number(arrayOfDigits.join(''));

console.log(singleNumber); //12345

回答by Mohan Ram

const arrString = ["1","2","3","4","5"];
const arrInteger = arrString.map(x => Number.parseInt(x, 10));

Above one should be simple enough,

上面一个应该够简单了，

One tricky part is when you try to use point free function for mapas below

一个棘手的部分是当您尝试对地图使用无点功能时，如下所示

const arrString = ["1","2","3","4","5"];
const arrInteger = arrString.map(Number.parseInt);

In this case, result will be [1, NaN, NaN, NaN, NaN]since function argument signature for mapand parseIntdiffers

在这种情况下，结果将是[1, NaN, NaN, NaN, NaN]因为函数参数签名为map和parseInt不同

map expects - (value, index, array)where as parseInt expects - (value, radix)

地图期望 - (value, index, array)parseInt 期望 - (value, radix)

回答by nitzan

Using jQuery, you can like the map()methodlike so;

使用jQuery，你可以喜欢这样的map()方法；

 $.map(arr, function(val,i) { 
     return parseInt(val); 
 });