如何显示这个数组的元素？

Question

var arr = [2, 6, 4, 4, 4, 9]var newArr = (arr.sort())for (var i = 0; i < newArr.length; i++)  if (newArr[i] == newArr[i + 1]) {    var rem = [console.log(i)] //- (a)  }console.log(rem[0])i我想要数组中数字重复的所有值newArr。语句 (a) 给出了索引，我想将它们存储在名为 的数组中rem。然而console.log(rem[0])是未定义的。我能做些什么？

Answer 1

你是这个意思？

var arr = [2, 6, 4, 4, 4, 9]

var newArr = (arr.sort())

var rem = []; // create your rem array outside

for (var i = 0; i < newArr.length; i++) {

  if (newArr[i] == newArr[i + 1]) {

    rem.push(i); // if "i" matches your criteria, add it to the array.

  }

}

console.log(rem); // rem has the full list of indices

Answer 2

也许是这样的？

var arr = [2, 6, 4, 4, 4, 9]

var newArr = (arr.sort())

vare rem = []

for (var i = 0; i < newArr.length; i++)

  if (newArr[i] == newArr[i + 1]) {

    rem.push(newArr[i]);

  }

console.log(rem[0])