获取对象数组中所有指定元素的总和 [英] Get the sum of all specified elements in an array of objects

问题描述

我有一组对象作为跟随者

I have an array of objects as folllows

[
    {"width":128.90663423245883,"height":160,"X":0,"Y":140},
    {"width":277.0938568683375,"height":263,"X":128.90663423245883,"Y":37},
    {"width":264.8267031014369,"height":261,"X":277.0938568683375,"Y":39},
    {"width":229.14003389179788,"height":60,"X":264.8267031014369,"Y":240},
    {"width":10.032771905968888,"height":177,"X":229.14003389179788,"Y":123}
]

我希望编写一个函数，该函数在当前对象之前获取对象中所有宽度"元素的总和.

I am looking to write a function that gets the sum of all 'width' elements in the object before the current.

类似的东西:

function getAllBefore(current) {
    // here i want to get the sum of the previous 4 'width' elements in the object
}
getAllBefore(obj[5]);

推荐答案

要获得更简单，更可重用的代码，请将对象和索引传递给该方法，如下所示:

For an easier and more reusable code pass to the method the object and the index, as follows:

function getAllBefore(obj, index){
  var sum=0;
  for(var i=0; i<index; i++){
    sum+=obj[i].width;
  }

  return sum;
}

并这样称呼它:

getAllBefore(obj, 5);

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