randomIntsRange.mjs

  1. import isint from './isint.mjs'
  2. import ispint from './ispint.mjs'
  3. import cint from './cint.mjs'
  4. import random from './random.mjs'
  7. /**
  8.  * 產生位於指定範圍內隨機整數陣列，各元素值域為[vstart,vend]，代表值會大於等於vstart且小於等於vend
  9.  *
  10.  * Unit Test: {@link https://github.com/yuda-lyu/wsemi/blob/master/test/randomIntsRange.test.mjs Github}
  11.  * @memberOf wsemi
  12.  * @param {Integer} [vstart=0] 輸入範圍最小值整數，預設0
  13.  * @param {Integer} [vend=100] 輸入範圍最大值整數，預設100
  14.  * @param {Integer} [n=1] 輸入產生數量整數，預設1
  15.  * @returns {Integer} 回傳位於指定範圍內隨機整數
  16.  * @example
  17.  *
  18.  * let rs
  19.  *
  20.  * rs = randomIntsRange()
  21.  * console.log('randomIntsRange', rs)
  22.  * // => randomIntsRange [ [0,100] ] (預設範圍為0至100)
  23.  *
  24.  * rs = randomIntsRange(0, 100)
  25.  * console.log('randomIntsRange(0, 100)', rs)
  26.  * // => randomIntsRange(0, 100) [ [0,100] ]
  27.  *
  28.  * rs = randomIntsRange(0, 100, 2)
  29.  * console.log('randomIntsRange(0, 100, 2)', rs)
  30.  * // => randomIntsRange(0, 100, 2) [ [0,100], [0,100] ]
  31.  *
  32.  * rs = randomIntsRange(123, 4567)
  33.  * console.log('randomIntsRange(123, 4567)', rs)
  34.  * // => randomIntsRange(123, 4567) [ [123,4567] ]
  35.  *
  36.  * rs = randomIntsRange(123, 4567, 2)
  37.  * console.log('randomIntsRange(123, 4567, 2)', rs)
  38.  * // => randomIntsRange(123, 4567, 2) [ [123,4567], [123,4567] ]
  39.  *
  40.  */
  41. function randomIntsRange(vstart = 0, vend = 100, n) {
  43.     //vstart
  44.     if (!isint(vstart)) {
  45.         vstart = 0
  46.     }
  47.     vstart = cint(vstart)
  49.     //vend
  50.     if (!isint(vend)) {
  51.         vend = 100
  52.     }
  53.     vend = cint(vend)
  55.     //n
  56.     if (!ispint(n)) {
  57.         n = 1
  58.     }
  59.     n = cint(n)
  61.     //check
  62.     if (vstart > vend) {
  63.         throw new Error(`vstart[${vstart}] > vend[${vend}]`)
  64.     }
  66.     //rs
  67.     let rs = []
  68.     for (let i = 1; i <= n; i++) {
  70.         //random, [0,1)
  71.         let pr = random()
  73.         //r
  74.         let rng = vend - vstart + 1 //要額外+1才能使取ceil時讓各整數出現機率一致
  75.         let r = pr * rng + vstart
  76.         r = Math.floor(r)
  78.         //push
  79.         rs.push(r)
  81.     }
  83.     return rs
  84. }
  87. export default randomIntsRange