搜索一个阵列，其中包括子阵列的最大数量和收益的新阵列 [英] Search An Array Consisting of Sub-Arrays For the Largest Number and Return in a New Array

问题描述

我工作的编码挑战，采取定数组它由子阵列，搜索每个子阵列中数量最多，最后返回只由最大数的新数组。我的想法过程是创造出来的变量每个子阵列的，写一个for循环的每个值在阵列内比较，那么最大的价值推到一个新的数组。写我的第一个for循环后，我测试了我的code，看到我收到整个第一子阵的一个意想不到的结果被推到我新的数组。我找了这个错误之前，我写在未来三环路。谢谢。编辑：这是初学者的JavaScript codeRS和建议表示您的解决方案使用比较运算符

 函数largestOfFour（ARR）{
      变种1 =改编[0];
      变种2 =改编[1];
      变种3 = ARR [2];
      变种4 =改编[3];
      变种newArr = [];      对于（VAR I = 0; I＆LT; one.length;我++）{
        变种oneLrg = 0;
        如果（一个[I]≥oneLrg）{
          oneLrg =一个[我]
          }
        newArr.push（oneLrg）;
      }  返回ARR;
}的console.log（largestOfFour（[4,5，1,3]，[13，27，18，26]，[32，35，37，39]，[1000，1001，857，1]））; //这个测​​试的情况下返回[4,5,1,3]，而不仅仅是[5]
 

解决方案

使用<一个href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Comparison_Operators#Greater_than_operator_%28%3E%29\"相对=nofollow> ＆GT; ：

VAR newArr = [];
对于（VAR I = 0; I＆LT; arr.length ++ I）{//迭代数组
  VAR最大=负无穷大; //初始最大
  对于（VAR J = 0; J＆LT;常用3 [I]。长度; ++ j）条//迭代子阵
    如果（ARR [I] [J]＆GT;最大值）//比较
      最大= ARR [I] [J]。 //更新最大
  newArr.push（最大）; //存放实际最大
}


使用 数学的.max ：

VAR newArr = [];
对于（VAR I = 0; I＆LT; arr.length ++ I）{//迭代数组
  VAR最大=负无穷大; //初始最大
  对于（VAR J = 0; J＆LT;常用3 [I]。长度; ++ j）条//迭代子阵
    最大= Math.max（最大，编曲[I] [J]）; //更新最大
  newArr.push（最大）; //存放实际最大
}


添加<一个href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/apply\"相对=nofollow> 适用 ：

VAR newArr = [];
对于（VAR I = 0; I＆LT; arr.length ++ I）//迭代数组
  newArr.push（//商店...
    Math.max.apply（数学，编曲由[i]）// ...最大的子数组
  ）;


添加的ECMAScript 5 地图

VAR newArr = arr.map（功能（子数组）{
  返回Math.max.apply（数学，子阵）;
}）;


添加的ECMAScript 5 <一个href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/bind\"相对=nofollow>绑定，

VAR newArr = arr.map（Function.apply.bind（Math.max，数学））;


或添加的ECMAScript 6 箭头功能和 US $ p $垫运营商，

VAR newArr = arr.map（子数组=＆GT; Math.max（...子阵））;


I am working on a coding challenge to take a given array which consists of sub-arrays, search for the largest number in each sub-array, and finally return a new array consisting only of the largest numbers. My thought process was to create variables out of each subarray, write a for-loop comparing each value within the array, then push the largest value to a new array. After writing my first for-loop I tested my code and see that I am getting an unexpected result of the entire first subarray being pushed into my new array. I am looking for the mistake before I write the next three loops. Thank you. Edit: This is for beginner JavaScript coders and the suggestion indicates to use comparison operators in your solution.

function largestOfFour(arr) {
      var one = arr[0];
      var two = arr[1];
      var three = arr[2];
      var four = arr[3];
      var newArr = [];

      for (var i = 0; i < one.length; i++){
        var oneLrg = 0;
        if (one[i] > oneLrg){
          oneLrg = one[i];
          }
        newArr.push(oneLrg);
      }  

  return arr;
}

console.log(largestOfFour([[4, 5, 1, 3], [13, 27, 18, 26], [32, 35, 37, 39], [1000, 1001, 857, 1]])); //This test case returns [4,5,1,3] instead of just [5]

解决方案

Using >:

var newArr = [];
for(var i=0; i<arr.length; ++i) {           // Iterate array
  var maximum = -Infinity;                  // Initial maximum
  for(var j=0; j<arr[i].length; ++j)        // Iterate subarrays
    if(arr[i][j] > maximum)                 // Compare
      maximum = arr[i][j];                  // Update maximum
  newArr.push(maximum);                     // Store the real maximum
}

Using Math.max:

var newArr = [];
for(var i=0; i<arr.length; ++i) {           // Iterate array
  var maximum = -Infinity;                  // Initial maximum
  for(var j=0; j<arr[i].length; ++j)        // Iterate subarrays
    maximum = Math.max(maximum, arr[i][j]); // Update maximum
  newArr.push(maximum);                     // Store the real maximum
}

Adding apply:

var newArr = [];
for(var i=0; i<arr.length; ++i)     // Iterate array
  newArr.push(                      // Store ...
    Math.max.apply(Math, arr[i])    // ... the maximum of the subarray
  );

Adding ECMAScript 5 map,

var newArr = arr.map(function(subarray) {
  return Math.max.apply(Math, subarray);
});

Adding ECMAScript 5 bind,

var newArr = arr.map(Function.apply.bind(Math.max, Math));

Or adding ECMAScript 6 arrow functions and spread operator,

var newArr = arr.map(subarray => Math.max(...subarray));

这篇关于搜索一个阵列，其中包括子阵列的最大数量和收益的新阵列的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！