字符串和数组的api演示

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    <title>字符串和数组的api</title>
</head>
<body>
    <script>
        // 自选不少于5个字符串和数组的api实例演示,特别是数组遍历方法
        // 字符串
        let str = "php中文网";
        // 1.字符串长度
        out(str.length);
        // 2.索引获取元素
        out(str.charAt(0));
        // 3.元素获取索引
        out(str.indexOf("文"));
        out(str.search("文"));
        // 4.字符串拼装
        out(str.concat(' php.cn'));
        // 5.字符串替换
        out(str.replace("中文网",".cn"));
        // 6.字符串查询
        out(str.slice(0,3));
        // 7.substr
        out(str.substr(-3,3));
        // 8.split分割字符串为数组
        out(str.replace("中文网",".cn").split('.'));
        ///////////////////////////////////////////////////////////////////////
        // 数组
        let arr = [1,2,3,4,5,6,7,8,9];
        // 1.foreach,Map
        arr.forEach((item,index)=>{out(`${index}:${item}`)});
        out(arr.map((item,index)=>`index:${index},item:${item}`));
        // 2.every,some
        out(arr.every(item=>item>=3));
        out(arr.every(item=>item>=1));
        out(arr.some(item=>item>=3));
        out(arr.some(item=>item>=1));
        // 3.filter,find,findIndex
        out(arr.filter(item=>item>=3));
        out(arr.find(item=>item>=3));
        out(arr.findIndex(value=>value>=8));
        out(arr.findIndex(value=>value>=10));
        // 4.reduce
        out(arr.reduce((res,index)=>res+index,0));
        out(arr.reduce((res,index)=>res+index,100));
        // ConsoleOutHelper
        function out(outprint){
           return console.log(outprint);
        }
    </script>
</body>
</html>
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