js Array and Method to weight performance comparison

js in the array

Deduplication Array

Commonly used methods, and the deduplication efficiency Array Analysis:

First we build an array is mainly used for de-duplication test, the magnitude of our main experiment is 1000,10000,100000,500000. Specific method of generating an array of the following:

function buildDataArr (size) {
    var array = [];
    for (var i =0; i< size; i++) {
        var num = Math.round(Math.random() * size);
        array.push(num);
    }
    return array;
}
var arr1 = buildDataArr(1000);
var arr2 = buildDataArr(10000);
var arr3 = buildDataArr(100000);
var arr4 = buildDataArr(500000);

• Performed by using a de-emphasis filter index and methods

  function distinct(numberArr) {
      return numberArr.filter((item, index)=> {
          return numberArr.indexOf(item) === index
      })
  }

• By using an array of dual circulation to be heavy

  function distinctFor(numberArr) {
      for (let i=0, len=numberArr.length; i<len; i++) {
          for (let j=i+1; j<len; j++) {
              if (numberArr[i] == numberArr[j]) {
                  numberArr.splice(j, 1);
                  // splice 会改变数组长度，所以要将数组长度 len 和下标 j 减一
                  len--;
                  j--;
              }
          }
      }
      return numberArr
  }

• ... of weight and by using de include for

  function distinctInclude(numberArr) {
      let result = []
      for (let i of numberArr) {
          !result.includes(i) && result.push(i)
      }
      return result
  }

• Use the sort to be heavy

  function distinctSort(numberArr) {
      numberArr = numberArr.sort()
      let result = [numberArr[0]]
  
      for (let i=1, len=numberArr.length; i<len; i++) {
          numberArr[i] !== numberArr[i-1] && result.push(numberArr[i])
      }
      return result
  }

• Use new Set de re

  function distinctSet(numberArr) {
      return Array.from(new Set(numberArr))
  }

• Use heavy objects to

  function distinctObj(numberArr) {
      let result = []
      let obj = {}
      for (var i of numberArr) {
          if (!obj[i]) {
              result.push(i)
              obj[i] = 1
          }
      }
      return result
  }

Well, the above method of introduction is over, let's look at the performance:

	1000	10000	100000	500000
distinctFilter	0	40	3992	105859
distinctFor	2	59	5873	147234
distinctInclude	1	24	2320	54794
distinctSort	1	8	69	264
distinctSet	0	1	12	78
distinctObj	1	1	9	33