以下範例基於一個陣列:
let values = [2, 56, 3, 41, 0, 4, 100, 23];
如果要取得平均,我們必須加總所有數字和再除以數字的個數。步驟是:
- 取得陣列長度
- 加總數值
- 取得平均(
數值總和 / 陣列長度
)
let values = [2, 56, 3, 41, 0, 4, 100, 23];
let sum = values.reduce((previous, current) => current += previous);
let avg = sum / values.length;
// avg = 28
或:
let values = [2, 56, 3, 41, 0, 4, 100, 23];
let count = values.length;
values = values.reduce((previous, current) => current += previous);
values /= count;
// avg = 28
現在,如果要取得中間值的步驟:
let values = [2, 56, 3, 41, 0, 4, 100, 23];
values.sort((a, b) => a - b);
let lowMiddle = Math.floor((values.length - 1) / 2);
let highMiddle = Math.ceil((values.length - 1) / 2);
let median = (values[lowMiddle] + values[highMiddle]) / 2;
// median = 13,5
隨著位元運算符:
let values = [2, 56, 3, 41, 0, 4, 100, 23];
values.sort((a, b) => a - b);
let median = (values[(values.length - 1) >> 1] + values[values.length >> 1]) / 2
// median = 13,5