【array_merge】array_merge引起的一个bug【原创】

工作中采用数组合并，例子如下：

1. $aaa = M('lottery')->where($where)->field('id, title as name, type, statdate as starttime, enddate as endtime, status')->order('id desc')->select();
2. $bbb = M('shakelottery')->where($where)->field('id, action_name as name, 3 as type, starttime, endtime, status')->order('id desc')->select();
3. $ccc = M('cointree')->where($where)->field('id, action_name as name, 1000 as type, starttime, endtime, status')->order('id desc')->select();
4. $data = array_merge($aaa, $bbb, $ccc);

由于从数据库中获取数据的，所以每个数组的形式都是类似：

1. $ccc = array(
2. 0 =>
3. array (
4. 'id' => '166',
5. 'name' => '何摇钱001',
6. 'type' => '1000',
7. 'starttime' => '1475908080',
8. 'endtime' => '1478586480',
9. 'status' => '1',
10. ),
11. 1 =>
12. array (
13. 'id' => '160',
14. 'name' => '111',
15. 'type' => '1000',
16. 'starttime' => '1473234420',
17. 'endtime' => '1475826420',
18. 'status' => '1',
19. ),
20. 2 =>
21. array (
22. 'id' => '158',
23. 'name' => '积分',
24. 'type' => '1000',
25. 'starttime' => '1473234180',
26. 'endtime' => '1475826180',
27. 'status' => '1',
28. ),
29. 3 =>
30. array (
31. 'id' => '156',
32. 'name' => '不需要积分摇钱树',
33. 'type' => '1000',
34. 'starttime' => '1473231360',
35. 'endtime' => '1475823360',
36. 'status' => '1',
37. ),
38. );

都是类似这样的，所以合并类似的3个数组呢，是没问题的。但是今天合并的时候出来的是NULL，然后发现是$bbb在数据库中并没有数据，也就是$bbb = null，这样在合并的时候呢，最后出来的是null。

即：

1. $aaa = array(
2. 0 =>
3. array (
4. 'id' => '386',
5. 'name' => '何大转盘002',
6. 'type' => '1',
7. 'starttime' => '1475921400',
8. 'endtime' => '1478513400',
9. 'status' => '1',
10. ),
11. 1 =>
12. array (
13. 'id' => '384',
14. 'name' => '何刮刮卡01',
15. 'type' => '2',
16. 'starttime' => '1475907660',
17. 'endtime' => '1478499660',
18. 'status' => '1',
19. ),
20. 2 =>
21. array (
22. 'id' => '382',
23. 'name' => '何大转盘01',
24. 'type' => '1',
25. 'starttime' => '1475907540',
26. 'endtime' => '1478499540',
27. 'status' => '1',
28. ),
29. 3 =>
30. array (
31. 'id' => '374',
32. 'name' => '幸运大转盘活动开始了',
33. 'type' => '1',
34. 'starttime' => '1473235800',
35. 'endtime' => '1475827800',
36. 'status' => '1',
37. )
38. );
39. $bbb = NULL;
40. $ccc = array(
41. 0 =>
42. array (
43. 'id' => '166',
44. 'name' => '何摇钱001',
45. 'type' => '1000',
46. 'starttime' => '1475908080',
47. 'endtime' => '1478586480',
48. 'status' => '1',
49. ),
50. 1 =>
51. array (
52. 'id' => '160',
53. 'name' => '111',
54. 'type' => '1000',
55. 'starttime' => '1473234420',
56. 'endtime' => '1475826420',
57. 'status' => '1',
58. ),
59. 2 =>
60. array (
61. 'id' => '158',
62. 'name' => '积分',
63. 'type' => '1000',
64. 'starttime' => '1473234180',
65. 'endtime' => '1475826180',
66. 'status' => '1',
67. ),
68. 3 =>
69. array (
70. 'id' => '156',
71. 'name' => '不需要积分摇钱树',
72. 'type' => '1000',
73. 'starttime' => '1473231360',
74. 'endtime' => '1475823360',
75. 'status' => '1',
76. ),
77. );
78. $data = array_merge($aaa, $bbb, $ccc);
79. dump($data);

结果会是null。

查文档发现该array_merge该函数只能接受数组类型的参数，如果不是，则会返回null。所以呢，需要对参数进行数组化，即：

1. $data = array_merge((array)$aaa, (array)$bbb, (array)$ccc);

这样就可以了，即使$bbb = null也会跳过$bbb进行合并的。