我有下面的字符串
var a = "1,2,3,4";
当我…
var b = a.split(',');
我得到b为["1","2","3","4"]
我能做点什么让b等于[1,2,3,4]吗?
我有下面的字符串
var a = "1,2,3,4";
当我…
var b = a.split(',');
我得到b为["1","2","3","4"]
我能做点什么让b等于[1,2,3,4]吗?
当前回答
使用arraw函数的Matt Zeunert版本(ES6)
const nums = a.split(',').map(x => parseInt(x, 10));
其他回答
你可以使用数组。映射将每个元素转换为一个数字。
var a = "1,2,3,4";
var b = a.split(',').map(function(item) {
return parseInt(item, 10);
});
检查文档
或者像User: thg435所指出的那样更优雅
var b = a.split(',').map(Number);
Number()将完成其余的工作:检查这里
注意:对于不支持map的旧浏览器,你可以自己添加一个实现:
Array.prototype.map = Array.prototype.map || function(_x) {
for(var o=[], i=0; i<this.length; i++) {
o[i] = _x(this[i]);
}
return o;
};
由于所有的答案都允许包含NaN,所以我想补充一句,如果您想快速地将一个混合值的数组转换为数字,您可以这样做。
var a = "1,2,3,4,foo,bar";
var b = a.split(',');
var result = b.map(_=>_|0) // Floors the number (32-bit signed integer) so this wont work if you need all 64 bits.
// or b.map(_=>_||0) if you know your array is just numbers but may include NaN.
使用Array.from,试试这个:
Let b = ["1", "2", "3", "4"]; b = Array.from(b,Number); console.log (b);
没有必要使用lambdas和/或给parseInt的基数参数,只需使用parseFloat或Number代替。
原因:
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 It's shorter. 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'! >_<
注意:在Firefox中,parseInt的工作速度大约快4倍,但仍然比其他的慢。总共:+e < Number < parseFloat < parseInt
一个更简短的解决方案:映射并传递参数给Number:
Var a = "1,2,3,4"; Var b = a.s split(','); console.log (b); var c = b.map(Number); console.log (c);