Math.min.apply为null返回0 [英] Math.min.apply returns 0 for null

问题描述

我想从数组中获得最小值。如果数据包含 null 值，则 Math.min.apply 返回 0 for null value。请参阅此JSFiddle示例。即使数组中存在空值，如何获得真正的最小值？

I would like to get minimum value from an array. If the data contains null value, Math.min.apply returns 0 for null value. Please see this JSFiddle example. How can I get true minimum value even if null value exists in array?

代码（与JSFiddle示例中相同）：

Code (same as in JSFiddle example):

var arrayObject= [ {"x": 1, "y": 5}, {"x": 2, "y": 2}, {"x": 3, "y": 9}, {"x": 4, "y": null}, {"x": 5, "y": 12} ];

var max = Math.max.apply(Math, arrayObject.map(function(o){return o.y;}));
var min = Math.min.apply(Math, arrayObject.map(function(o){return o.y;}));

$("#max").text(max);
$("#min").text(min);

推荐答案

嗯， null 是 0 。如果您不想要考虑 null 值，则必须将其过滤掉：

Well, the numerical value for null is 0. If you don't want null values to be be considered, you have to filter them out:

var values = arrayObject.map(function(o){
    return o.y;
}).filter(function(val) {
    return val !== null
});

参考： Array＃filter

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