我们如何获得 JSON 数组中的最大数字？ [关闭]

Question

我想用 JavaScript 或 jQuery 计算最大数量的“概率”，并获得最大数量的“标签”。

下面，例如“郁金香”。

感谢您的帮助。

result_predictions=[
  {
    "label": "roses",
    "prob": 0.0056262025609612465
  },
  {
    "label": "daisy",
    "prob": 0.005660845898091793
  },
  {
    "label": "dandelion",
    "prob": 0.005297524854540825
  },
  {
    "label": "tulips",   // What I want to pick
    "prob": 0.9730507731437683  //the highest number
  },
  {
    "label": "sunflowers",
    "prob": 0.010364603251218796
  }
]

Answer 1

解决方案

---

这是一个干净的 ES6 方法，我相信这是用最少的代码做到这一点的方法，但有很多方法

sort

const results = [
  {
    "label": "roses",
    "prob": 0.0056262025609612465
  },
  {
    "label": "daisy",
    "prob": 0.005660845898091793
  },
  {
    "label": "dandelion",
    "prob": 0.005297524854540825
  },
  {
    "label": "tulips",
    "prob": 0.9730507731437683
  },
  {
    "label": "sunflowers",
    "prob": 0.010364603251218796
  }
]

const highest = results.sort((a, b) => b.prob - a.prob)[0].label

console.log(highest)

其他方法

---

map, Math.max & filter

const results = [
  {
    "label": "roses",
    "prob": 0.0056262025609612465
  },
  {
    "label": "daisy",
    "prob": 0.005660845898091793
  },
  {
    "label": "dandelion",
    "prob": 0.005297524854540825
  },
  {
    "label": "tulips",
    "prob": 0.9730507731437683
  },
  {
    "label": "sunflowers",
    "prob": 0.010364603251218796
  }
]

const probs = results.map(res => res.prob)
const highestProb = Math.max(...probs)
const result = results.filter(res => res.prob == highestProb)[0].label

console.log(result)

reduce

const results = [
  {
    "label": "roses",
    "prob": 0.0056262025609612465
  },
  {
    "label": "daisy",
    "prob": 0.005660845898091793
  },
  {
    "label": "dandelion",
    "prob": 0.005297524854540825
  },
  {
    "label": "tulips",
    "prob": 0.9730507731437683
  },
  {
    "label": "sunflowers",
    "prob": 0.010364603251218796
  }
]

const highest = results.reduce((a, b) => a.prob <= b.prob ? b : a).label

console.log(highest)

Answer 2

使用Array.prototype.reduce():

const result_predictions = 
      [ { label: "roses",      prob: 0.0056262025609612465 } 
      , { label: "daisy",      prob: 0.005660845898091793  } 
      , { label: "dandelion",  prob: 0.005297524854540825  } 
      , { label: "tulips",     prob: 0.9730507731437683    } 
      , { label: "sunflowers", prob: 0.010364603251218796  } 
      ] 
       

const label_ofMax = result_predictions
                     .reduce((a,c)=>(a.prob<c.prob)?c:a)
                     .label

console.log( label_ofMax,  )