写一个方法获取指定数组中间的值（一个或者两个）

yyjiugui 2020-03-27 04:50:09

function getValue(arr) {
  if (!Array.isArray(arr)) {
    alert('请输入数组')
    return
  }
  const len = arr.length
  const even = len % 2 === 0

  if (even) {
    // 处理偶数
    const maxIndex = len / 2
    const minIndex = maxIndex - 1
    return [arr[minIndex], arr[maxIndex]]
  } else {
    // 处理奇数
    const odd = Math.floor(len / 2)
    return arr[odd]
  }
}

0 0 0

zackzergzeng 2020-03-27 12:26:45

Array.prototype.getArrayMiddle = function(){
  return this.length % 2 ? this[parseInt(this.length/2)] : [this[parseInt(this.length/2)-1], this[parseInt(this.length/2)]];
}

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zwlhc 2020-03-28 06:09:07

function findMiddle (arr)  {
   const mid = parseInt(arr.length/2, 10)  
   return arr.length%2? [arr[mid]] : [arr[mid-1], arr[mid]]
}

0 0 0

Sunxinqiang 2020-03-31 09:57:29

实现

function getArrayMiddle (arr = []) {
    if (!Array.isArray(arr)) {
        return []
    }
    let len = arr.length
    // 长度小于3 直接返回 [] [1] [1,2]
    if (len < 3) {
        return arr.slice()
    }
    let isOdd = len % 2
    let index = len / 2
    // 奇数
    if (isOdd) {
        return [arr[Math.floor(index)]]
    } else {
        return [arr[index - 1], arr[index]]
    }
}

console.log(
 getArrayMiddle([]), // []
 getArrayMiddle([1]), // [1]
 getArrayMiddle([1,2]), // [1,2]
 getArrayMiddle([1,2,3,4,5]), // [3]
 getArrayMiddle([1,2,3,4,5,6,7,8,9,0]) // [5,6]
)

0 0 0

LicyWang 2020-05-07 01:59:36

0 0 0

zhiyual 2020-06-16 12:15:40

function getMidValue(arr) {
    let rsl = [];
    let l = arr.length;
    if (l % 2 == 0) {
        // 偶数
        rsl.push(arr[l/2-1], arr[l/2]);
    } else {
        // 奇数
        rsl.push(arr[(l-1)/2]);
    }
    return rsl;
}

0 0 0

yu1176887527 2020-07-02 07:59:39

if (Array.prototype.getMiddleArray !== 'function') {
    Array.prototype.getMiddleArray = function() {
        let middleStartIndex = Math.floor(this.length / 2),
            middleEndIndex = Math.ceil(this.length / 2);
        if (middleStartIndex === middleEndIndex) {
            middleStartIndex--;
            middleEndIndex++;
        }
        return this.slice(middleStartIndex, middleEndIndex);
    }
}

[1,2,3].getMiddleArray()  // [2]
[1,2,3,4].getMiddleArray()  // [2,3]

0 1 0

mxm646690173 2020-07-14 06:56:54

getCenterNum(array);
  function getCenterNum(arr) {
    //整除，即为中间数为2个，否则为1个
    if (arr.length % 2 == 0) {
      console.log(arr[arr.length / 2 -1] + "," + arr[arr.length / 2]);
    } else {
      console.log(arr[Math.floor(arr.length / 2)]);
    }
  }

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[js] 写一个方法获取指定数组中间的值（一个或者两个）

实现