我有一个JavaScript数组,如:
[["$6"], ["$12"], ["$25"], ["$25"], ["$18"], ["$22"], ["$10"]]
如何将单独的内部数组合并为一个,例如:
["$6", "$12", "$25", ...]
我有一个JavaScript数组,如:
[["$6"], ["$12"], ["$25"], ["$25"], ["$18"], ["$22"], ["$10"]]
如何将单独的内部数组合并为一个,例如:
["$6", "$12", "$25", ...]
当前回答
这并不难,只需遍历数组并合并它们:
var result = [], input = [["$6"], ["$12"], ["$25"], ["$25"], ["$18"]];
for (var i = 0; i < input.length; ++i) {
result = result.concat(input[i]);
}
其他回答
以下代码将压平深度嵌套的数组:
/**
* [Function to flatten deeply nested array]
* @param {[type]} arr [The array to be flattened]
* @param {[type]} flattenedArr [The flattened array]
* @return {[type]} [The flattened array]
*/
function flattenDeepArray(arr, flattenedArr) {
let length = arr.length;
for(let i = 0; i < length; i++) {
if(Array.isArray(arr[i])) {
flattenDeepArray(arr[i], flattenedArr);
} else {
flattenedArr.push(arr[i]);
}
}
return flattenedArr;
}
let arr = [1, 2, [3, 4, 5], [6, 7]];
console.log(arr, '=>', flattenDeepArray(arr, [])); // [ 1, 2, [ 3, 4, 5 ], [ 6, 7 ] ] '=>' [ 1, 2, 3, 4, 5, 6, 7 ]
arr = [1, 2, [3, 4], [5, 6, [7, 8, [9, 10]]]];
console.log(arr, '=>', flattenDeepArray(arr, [])); // [ 1, 2, [ 3, 4 ], [ 5, 6, [ 7, 8, [Object] ] ] ] '=>' [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ]
有一个新的本地方法叫做flat,可以准确地执行此操作。
(截至2019年底,flat现已发布在ECMA 2019标准中,并且core-js@3(babel的库)将其包含在他们的polyfill库中)
const arr1 = [1, 2, [3, 4]];
arr1.flat();
// [1, 2, 3, 4]
const arr2 = [1, 2, [3, 4, [5, 6]]];
arr2.flat();
// [1, 2, 3, 4, [5, 6]]
// Flatten 2 levels deep
const arr3 = [2, 2, 5, [5, [5, [6]], 7]];
arr3.flat(2);
// [2, 2, 5, 5, 5, [6], 7];
// Flatten all levels
const arr4 = [2, 2, 5, [5, [5, [6]], 7]];
arr4.flat(Infinity);
// [2, 2, 5, 5, 5, 6, 7];
适用于所有数据类型的递归版本
/*jshint esversion: 6 */
// nested array for testing
let nestedArray = ["firstlevel", 32, "alsofirst", ["secondlevel", 456,"thirdlevel", ["theinnerinner", 345, {firstName: "Donald", lastName: "Duck"}, "lastinner"]]];
// wrapper function to protect inner variable tempArray from global scope;
function flattenArray(arr) {
let tempArray = [];
function flatten(arr) {
arr.forEach(function(element) {
Array.isArray(element) ? flatten(element) : tempArray.push(element); // ternary check that calls flatten() again if element is an array, hereby making flatten() recursive.
});
}
// calling the inner flatten function, and then returning the temporary array
flatten(arr);
return tempArray;
}
// example usage:
let flatArray = flattenArray(nestedArray);
深度扁平化和面向对象怎么样?
[23, [34, 454], 12, 34].flatten();
// --> [23,34, 454, 12, 34]
[23, [34, 454,[66,55]], 12, 34].flatten();
// --> [23, 34, 454, [66,55], 12, 34]
深压平:
[23, [34, 454,[66,55]], 12, 34].flatten(true);
// --> [23, 34, 454, 66, 55, 12, 34]
DEMO
CDN
如果所有数组元素都是Integer、Float,。。。或/和字符串,所以只需执行以下操作:
var myarr=[1,[7,[9.2]],[3],90];
eval('myarr=['+myarr.toString()+']');
print(myarr);
// [1, 7, 9.2, 3, 90]
DEMO
简单并处理多个嵌套级别:
// deeply nested array
const myArray = [1, 2, [3, 4, [5, 6, [[[7,8, [[[[[9, 10]]]]]]]]]]] ;
const flatten = (arr) => {
for (let index = 0; index < arr.length; index++) {
const elem = arr[index];
if (Array.isArray(elem)) {
arr.splice(index, 1, ...elem);
index--;
}
}
};
flatten(myArray);
console.log(myArray); // [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]