9_数组内置方法.html 1.3 KB

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  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. <script>
  10. var arr = [1,2,3,4,5,6,7,8,9];
  11. var arr1 = ["a","b","c","d"];
  12. // console.log(arr.length)//length 方法返回数组长度
  13. // var arr2 = arr.concat(arr1);
  14. // console.log(arr2);
  15. // 向数组最后添加一个新值
  16. // arr1.push("e");
  17. // console.log(arr1);
  18. // 向数组前方添加新值
  19. // arr1.unshift("aa");
  20. // console.log(arr1);
  21. // 删除数组中最后一个值
  22. // arr1.pop();
  23. // console.log(arr1);
  24. // 删除数组第一个值
  25. // var num1 = arr1.shift();
  26. // console.log(arr1,num1);
  27. //数组转字符串
  28. // var str1 = arr1.join("-");
  29. // var str1 = arr1.join("");
  30. // console.log(str1);
  31. //字符串转数组
  32. // var str2 = "hello";
  33. // var arr3 = str2.split("");
  34. // console.log(arr3);
  35. // console.log(arr.includes(99));
  36. // console.log(arr.indexOf(99));
  37. // console.log(arr.reverse());
  38. // console.log(arr.slice(2,6),arr)
  39. // console.log(arr.splice(2,1,'a','b','c'),arr)
  40. </script>
  41. </body>
  42. </html>