Javascript数组中省略了元素 - 问题

Question

I want to sort an array from lowest number to highest. But when I execute the following code, some of my array elements get missed! I don't know why. I need help.`// Sort an array from lowest to highest

 function findSmallest(numArr) { let smallestNumber = numArr[0] for (let i = 0; i < numArr.length; i++) { if (numArr[i + 1] < smallestNumber) { smallestNumber = numArr[i + 1] } } return smallestNumber; } function getSortedArray(arr) { let sortedArray = [] for (j = 0; j < arr.length; j++) { let smallest = findSmallest(arr) let smallestNumbmerIndex; for (let i = 0; i < arr.length; i++) { if (arr[i] === smallest) { smallestNumbmerIndex = i } } arr.splice(smallestNumbmerIndex, 1) sortedArray.push(smallest) } return sortedArray } let myArr = [23, 2, 12, 4] console.log(getSortedArray(myArr)) // console output => [2, 4] , the rest elements get omitted

Answer 1

since arr shrinks in each iteration, your for loop won't run 4 iterations, only 2 -

use while(arr.length){ instead of the for j loop

 function findSmallest(numArr) { let smallestNumber = numArr[0] for (let i = 0; i < numArr.length; i++) { if (numArr[i + 1] < smallestNumber) { smallestNumber = numArr[i + 1] } } return smallestNumber; } function getSortedArray(arr) { let sortedArray = [] while(arr.length) { let smallest = findSmallest(arr) let smallestNumbmerIndex; for (let i = 0; i < arr.length; i++) { if (arr[i] === smallest) { smallestNumbmerIndex = i } } arr.splice(smallestNumbmerIndex, 1) sortedArray.push(smallest) } return sortedArray } let myArr = [23, 2, 12, 4] console.log(getSortedArray(myArr)) // console output => [2, 4] , the rest elements get omitted

Answer 2

We can use a while loop, or we can store the length of array into a variable before the for loop, so that it will not change:

 function findSmallest(numArr) { let smallestNumber = numArr[0] for (let i = 0; i < numArr.length; i++) { if (numArr[i + 1] < smallestNumber) { smallestNumber = numArr[i + 1] } } return smallestNumber; } function getSortedArray(arr) { let sortedArray = [] // we can store the array length into a variable let length = arr.length for (j = 0; j < length; j++) { let smallest = findSmallest(arr) let smallestNumbmerIndex; for (let i = 0; i < arr.length; i++) { if (arr[i] === smallest) { smallestNumbmerIndex = i } } arr.splice(smallestNumbmerIndex, 1) sortedArray.push(smallest) } return sortedArray } let myArr = [23, 2, 12, 4] console.log(getSortedArray(myArr))