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js 数组去重方法汇总

<!DOCTYPE html>
<html lang="zh">

    <head>
        <meta charset="UTF-8" />
        <meta name="viewport" content="width=device-width, initial-scale=1.0" />
        <meta http-equiv="X-UA-Compatible" content="ie=edge" />
        <title>js 数组去重</title>
    </head>
    <body>

        <script src="https://cdn.bootcss.com/lodash.js/4.17.10/lodash.min.js"></script>
        <script type="text/javascript">
            //方法一
            function arrayUnique1(arr) {
                const ret = []
                for(let i = 0; i < arr.length; i++) {
                    const item = arr[i],
                        idx = ret.indexOf(item)

                    if(idx < 0) {
                        ret.push(item)
                    }
                }
                return ret
            }
            //方法二
            function arrayUnique2(arr) {
                const map = {},
                    ret = []
                for(let i = 0; i < arr.length; i++) {
                    const item = arr[i]
                    if(map[item] == null) {
                        map[item] = i
                        ret.push(item)
                    }
                }
                return ret
            }
            //方法三:
            function arrayUnique3(arr) {
                return arr.filter((item, i) => arr.indexOf(item) === i)
            }
            //方法四
            function arrayUnique4(arr) {
                return [...new Set(arr)]
            }
            const arr = [1, 3, 1, 2, 2, 4, 3, 4, 1]
            console.log(arrayUnique4(arr))
        </script>
    </body>

</html>

 

posted @ 2018-08-22 14:47  孟繁贵  阅读(222)  评论(0编辑  收藏  举报
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