Question

我有一个String数组的数组，我想从该数组中获取忽略大小写的唯一元素。我该怎么取例如：

数组列表：

[
       ["java,C,Node,ReactJs"]
        ["c","Spring"]
        ["undefined"]
        ["asdja"]
        ["Java","Spring"]
        ["adjasjh"]
        ["adjasjh"]
        ["java"] 
]

ExpectedList：

[java,C,node,reactjs,spring,..]

Answer 1

Join数组，用逗号更改to lower case，split，转换为Set以获取唯一字词，然后spread返回到阵列：

＆＃13;

const arr = [["java,NO,C,Node,ReactJs"],["c","Spring"],["undefined"],["asdja"],["Java","Spring"],["adjasjh", "Spring-roll"],["adjasjh"],["java", "javascript", "java-script"]];

const result = [...new Set(arr.join().toLowerCase().split(','))];

console.log(result);

＆＃13;

较旧的答案 - 在所有情况下都不会工作：

您可以join数组数组，并使用String.match()和negative lookahead RegExp来获取唯一字符串：

＆＃13;

const arr = [["java,NO,C,Node,ReactJs"],["c","Spring"],["undefined"],["asdja"],["Java","Spring"],["adjasjh", "Spring-roll"],["adjasjh"],["java", "javascript", "java-script"]];

const result = arr.join()
  .match(/([^,]+\b)(?!.+\1[,|$])/ig);

console.log(result);

＆＃13;

Answer 2

您可以使用reduce和map方法迭代数组和单词，并使用Set最终返回唯一元素数组。

＆＃13;

const array = [["java,C,Node,ReactJs"], ["c","Spring"], ["undefined"], ["asdja"], ["Java","Spring"], ["adjasjh"], ["adjasjh"], ["java"] ]

const result = [...new Set(array.reduce((r, e) => {
  return r.concat(...e.map(s => s.split(',').map(w => w.toLowerCase())))
}, []))]
console.log(result)

＆＃13;

Answer 3

您可以平展数据并使用Map保留第一个唯一值而不会改变它。

const flat = (r, a) => Array.isArray(a) ? a.reduce(flat, r) : r.concat(a.split(','));

var data = [["java,C,Node,ReactJs"], ["c", "Spring"], ["undefined"], ["asdja"], ["Java", "Spring"], ["adjasjh"], ["adjasjh"], ["java"]],
    unique = Array.from(data
        .reduce(flat, [])
        .reduce((m, v) => ((l => m.has(l) || m.set(l, v))(v.toLowerCase()), m), new Map)
        .values()
    );

console.log(unique);

.as-console-wrapper { max-height: 100% !important; top: 0; }

Answer 4

您可以展平数组，将每个值转换为小写，使用Set删除重复项，然后Array.from将其转换回数组。

如果您的["java,C,Node,ReactJs"]实际上是：["java","C","Node","ReactJs"]，您可以这样做：

＆＃13;

const array = [
       ["java","C","Node","ReactJs"],
       ["c","Spring"],
       ["undefined"],
       ["asdja"],
       ["Java","Spring"],
       ["adjasjh"],
       ["adjasjh"],
       ["java"] 
];


const unique = Array.from(
  new Set([].concat.apply([], array).map(item => item.toLowerCase()))
  //       ^^^ flatten array     
);

console.log(unique);

＆＃13;

从Array of Array中获取唯一元素

4 个答案: