如何求一个不规则的二维数组的最大值

Question

给定一个数组，例如：

var arr = [
    ['1','15','56'],
    ['1','15','56'],
    ['3','-','56'],
    ['1','78','-'],
    ['1','-','56'],
]

如图所示不规则的二维数组求其最大值，有什么优雅点的方法吗？

Answer 1

es6很简单，如果二维数组是纯数字的话这样

const max = Math.max(...[].concat(...arr));
console.log(max)

不过我看你数组中包含-这样的字符，就要先过滤一遍

const max = Math.max(...[].concat(...arr.map(_arr => _arr.map(v => isNaN(v) ? 0 : v))));
console.log(max)

es5就乖乖循环遍历吧，怎么写都是丑的

var max = 0;
arr.forEach(function (_arr) {
  _arr.forEach(function (v) {
    if (!isNaN(v) && v > max) max = v
  })
});
console.log(max)

Answer 2

var arr = [
    ['1','15','56'],
    ['1','15','56'],
    ['3','-','56'],
    ['1','78','-'],
    ['1','-','56'],
];

function dparseInt(i){
  var j = parseInt(i);
  if( isNaN(j) ) return 0;
  return j;
var arr = [
    ['1','15','56'],
    ['1','15','56'],
    ['3','-','56'],
    ['1','78','-'],
    ['1','-','56'],
];

function dparseInt(i){
  var j = parseInt(i);
  if( isNaN(j) ) return 0;
  return j;
}

//数组全是字符先转为数字
var arr1 = arr.map(item=>{
  return item.map(i => dparseInt(i));
});

console.log(arr1);

//两个Math.max 搞定
var result = Math.max(...arr1.map(v=>Math.max(...v)))
console.log(result)

Answer 3

Math.max.apply(null, arr.map(function(el) {
    return Math.max.apply(null, el.filter(function(item) {return +item}))
}))

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