Published
Edited
Nov 17, 2021
Flatten Array
arr = [0, 1, 2, [3, 4, [5, 6], 7], 8, [9, 10], 11]
// 递归
flat = function flat(arr) {
return Array.isArray(arr) ? [].concat(...arr.map(flat)) : arr;
}
flat3 = function flat(arr) {
return arr.reduce((a, b) => a.concat(Array.isArray(b) ? flat(b) : b), []);
}
flat5 = function flat(arr) {
const res = [];
const dfs = (ar) => {
if (Array.isArray(ar)) ar.forEach(dfs);
else res.push(ar);
};
dfs(arr);
return res;
}
// 非递归
flat2 = (arr) => {
const res = [],
st = arr.slice().reverse();
while (st.length) {
const item = st.pop();
if (Array.isArray(item)) {
st.push(...item.slice().reverse());
} else res.push(item);
}
return res;
}
flat4 = function flat(arr) {
while (arr.some(Array.isArray)) {
arr = [].concat(...arr);
}
return arr;
}
flat(arr)
flat2(arr)
flat3(arr)
flat4(arr)
flat5(arr)
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