反向排序数组的sortedIndex？

Question

似乎Lodash的sortedIndex期望一个前向排序数组来进行二进制搜索。（例如[0,1,2,4])

> _.sortedIndex( [0,1,2,4], 3 )
> 3
> _.sortedIndex( [4,2,1,0], 3 )
> 4

Answer 1

SortedIndexby怎么样？

编辑：对于string比较，string.prototype.charcodeat（）可以帮助您将其转换为number，然后可以应用相同的逻辑。

const arr1 = [0, 1, 2, 4];
const arr2 = [4, 2 ,1, 0];

console.log(_.sortedIndex(arr1, 3 ));
// Similar, but with ranking function.
console.log(_.sortedIndexBy(arr2, 3, function(x) {return -x;}));

const charArr = ['D','B','A'];
// Take the first char and convert to Number
let index = _.sortedIndexBy(charArr, 'C', function(x) {
  // Type checks. (If you want it to be general to many types..
  if (typeof x === 'string') {
    return -x.charCodeAt(0);
  } else if (typeof x === 'number') {
    return -x;
  } // else ... for other types.....
});

console.log('To insert char C, put it to index: ', index);

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