concat不能改变数组的结构

    1. <!DOCTYPE html>
    2. <html lang="en">
    3. <head>
    4.     <meta charset="UTF-8">
    5.     <meta name="viewport" content="width=device-width, initial-scale=1.0">
    6.     <title>Document</title>
    7. </head>
    8. <body>
    9.     <!-- 面试题：常用数组的方法有哪些-->
    10.     <script>
    11.         // concat不能改变数组的结构
    12.         var arr = [1,2,3];
    13.         var c = [5,6,7];
    14.         var b = arr.concat(c);
    15.         console.log(arr);
    16.         console.log(b);
    17.     </script>
    18. </body>
    19. </html>

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