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webphp
Asked:2020-08-20 19:45:49 +0000 UTC2020-08-20 19:45:49 +0000 UTC

无论大小写如何，如何从数组中删除重复项？

  • 772

有一个像这样的数组

["А","а","а","А","и","И"]

需要删除重复项并只保留唯一值，不区分大小写

["А","и"]

区分大小写

array.filter((v, i, s) => v && s.indexOf(v) === i)

使它不区分大小写的最简单方法是什么？

javascript

4 个回答

  1. Best Answer

    正如 Enikeyshchik在评论中所写的那样，两个toLowerCase() 或之一toUpperCase()

    const arr = ["А","а","а","А","и","И"];

const a =  arr.reduce((result, element) => {
    const normalize = (x) => typeof x === 'string' ? x.toLowerCase() : x;

    const normalizedElement = normalize(element);
    if (result.every(otherElement => normalize(otherElement) !== normalizedElement))
      result.push(element);

    return result;
  }, []);
console.log(a);

    • 4

  2. 更简单的不区分大小写：

    array.map(_=>_.toUpperCase()).filter((v, i, s) => v && s.indexOf(v) === i);

    确实，根据浏览器对链的实现，我们可以通过一个数组获得两次完整的传递。

    • 2

  3. localCompare允许比较不区分大小写。

    代码示例：

    const arr = ["А","а","C","c","а","А","и","И"];

const isEqual = a => b => a.localeCompare(b, [], {sensitivity: 'base'}) === 0;

const result = arr.reduce((acc, x) => acc.some(isEqual(x)) ? acc : [...acc, x], []);
    • 2

  4. 我们将所有内容放到同一个寄存器中，并从集合数组中创建它：

    var data = ["А","а","а","А","и","И"];
var data = data.map(function(x){ return x.toUpperCase() });
var filtered_data = new Set(data);

for (var elem of filtered_data ) {
    console.log(elem)
}

    • 1

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