当第二阵列具有0时，无法合并JavaScript中的两个排序阵列

Question

我正在尝试编写一个可以合并两个排序的数组a和b的函数。但是，当数组B具有0时，它将仅显示数组A作为输出：

function mergeSortedArrays(a,b) {
  var merged = [],
  aElm = a[0],
  bElm = b[0],
  i = 1, //index for array a
  j = 1; //index for array b
  if (a.length == 0) {
    return b;
  }
  if (b.length == 0) {
    return a;
  }
  while (aElm || bElm) {
    if ((aElm && !bElm) || aElm < bElm) { //problem is that it thinks that 0 == !bElm
      merged.push(aElm);
      aElm = a[i++];
    } else {
      merged.push(bElm);
      bElm = b[j++];
    }
  }
  return merged;
}
mergeSortedArrays([2,5,6,9], [0,1,2,3,29]) //outputs [2,5,6,9]

我知道问题是因为0是假的，因此在条件if(aElm && !bElm)下，它将不断将AELM推入merged。编写条件的更好方法是什么，以便它识别为0是整数而不是现有的？

Answer 1

什么是编写条件的更好方法，以便将0识别为整数，而不是不存在？

编写条件的更好方法是不测试数组元素的存在，而是检查索引。

function mergeSortedArrays(a,b) {
  var merged = [],
      i = 0, //index for array a
      j = 0; //index for array b
  while (i < a.length || j < b.length) {
    if (j == b.length || a[i] < b[j]) {
      merged.push(a[i++]);
    } else {
      merged.push(b[j++]);
    }
  }
  return merged;
}

Answer 2

您可以显式检查undefined值。

function mergeSortedArrays(a, b) {
    var merged = [],
        aElm = a[0],
        bElm = b[0],
        i = 1, //index for array a
        j = 1; //index for array b
    if (a.length == 0) {
        return b;
    }
    if (b.length == 0) {
        return a;
    }
    while (aElm !== undefined || bElm !== undefined) {
        if ((aElm !== undefined && bElm === undefined) || aElm < bElm) {
            merged.push(aElm);
            aElm = a[i++];
        } else {
            merged.push(bElm);
            bElm = b[j++];
        }
    }
    return merged;
}
console.log(mergeSortedArrays([2, 5, 6, 9], [0, 1, 2, 3, 29]));

.as-console-wrapper { max-height: 100% !important; top: 0; }

Answer 3

如果没有负数号，请尝试> -1为(aElm >-1) && !(bElm>-1)

function mergeSortedArrays(a,b) {
  var merged = [],
  aElm = a[0],
  bElm = b[0],
  i = 1, //index for array a
  j = 1; //index for array b
  if (a.length == 0) {
    return b;
  }
  if (b.length == 0) {
    return a;
  }
  while ((aElm >-1) || (bElm>-1)) {
    if (((aElm >-1) && !(bElm>-1)) || aElm < bElm) { //problem is that it thinks that 0 == !bElm
      merged.push(aElm);
      aElm = a[i++];
    } else {
      merged.push(bElm);
      bElm = b[j++];
    }
  }
  return merged;
}
var result = mergeSortedArrays([2,5,6,9], [0,1,2,3,29]) //outputs [2,5,6,9]
console.log(result);

此解决方案

var a = [2,5,6,9];
var b = [0,1,2,3,29];
a = a.concat(b);
a.sort(function(a, b){return a - b});
console.log(a);