根据给定的日期格式'YYYY-mm-dd',获取该日期所在周的起始日期

常用日期操作

1. /**
2. * 获取一年中所有星期的起始日期
3. * @param $year 格式 'YYYY'
4. * 返回二维数组 下标 key1值对应一年中某一天所在周的实际年份 key2值对应一年中某一天所在的周数[一年中第几周]
5. * 返回false 日期格式错误
6. */
7. function get_all_weeks($year){
8. $week_arr = array();
9. $year = intval(trim($year));
10. $preg = "/^\d{4,}$/";
11. if(!preg_match($preg, $year)){
12. return false;
13. }
14. $begin_day = $year . '-01-01';
15. $end_day = $year . '-12-31';
16. //一年第一个星期一
17. if(date('w',strtotime($begin_day))!=1){
18. $begin_day = date('Y-m-d',strtotime("next monday", strtotime($begin_day)));
19. }
20. //第一个星期一所在周数
21. $begin_week_num = intval(date('W',strtotime($begin_day)));
22. //一年最后一个星期天
23. if(date('w',strtotime($end_day))!=0){
24. $end_day = date('Y-m-d',strtotime("last sunday",strtotime($end_day)));
25. //存在跨年的星期，跨年所在周星期一
26. $end_day_next = date('Y-m-d',strtotime($end_day)+24*60*60);
27. //跨年星期所属年份与所在周数
28. $stride_year = date('o',strtotime($end_day_next));
29. $stride_weeknum = intval(date('W',strtotime($end_day_next)));
30. }
31. //最后一个星期天所在周数
32. $end_week_num = intval(date('W',strtotime($end_day)));
33. //一年第一个周一为一年的第一周或者第二周
34. if($begin_week_num!=1){
35. $i=2;
36. }else{
37. $i=1;
38. }
39. $j = 0;
40. for($i;$i $start_date = date("Y-m-d", strtotime("$begin_day $j week"));
41. $end_day = date("Y-m-d", strtotime($start_date . '+6 day'));
42. $week_arr[$year][$i] = array(
43. $start_date,
44. $end_day
45. );
46. $j++;
47. }
48. if($end_day_next){
49. $week_arr[$stride_year][$stride_weeknum] = array(
50. $end_day_next,
51. date("Y-m-d", strtotime($end_day_next . '+6 day'))
52. );
53. }
54. return $week_arr;
55. }
56. //demo_调用
57. /*
58. $year = '2013';
59. if(get_all_weeks($year)){
60. var_dump(get_all_weeks($year));
61. }else{
62. echo '日期格式出错';
63. }
64. */
65. /**
66. * 获取某一天所在周的起始日期
67. * 依赖 function get_all_weeks
68. * @param $day 格式:'YYYY-mm-dd'
69. * 返回false 日期格式错误
70. * 正确,返回json "{"begin_day":"YYYY-mm-dd","end_day":"YYYY-mm-dd"}"
71. */
72. function get_day_week($day){
73. $date_arr = explode('-', trim($day));
74. if(!checkdate(intval($date_arr[1]), intval($date_arr[2]), intval($date_arr[0]))){
75. return false;
76. }
77. $year = date('Y',strtotime($day));
78. $weeks = get_all_weeks($year);
79. //某一天所属的年份与周数
80. $real_year = date('o',strtotime($day));
81. $week_num = intval(date('W',strtotime($day)));
82. if(!empty($weeks[$real_year][$week_num][0]))
83. $begin_day = $weeks[$real_year][$week_num][0];
84. if(!empty($weeks[$real_year][$week_num][1]))
85. $end_day = $weeks[$real_year][$week_num][1];
86. //跨年周数值存储于上一年中
87. if(empty($begin_day)||empty($end_day)){
88. $year = date('Y',strtotime($day))-1;
89. $weeks = get_all_weeks($year);
90. $real_year = date('o',strtotime($day));
91. $week_num = intval(date('W',strtotime($day)));
92. if(!empty($weeks[$real_year][$week_num][0]))
93. $begin_day = $weeks[$real_year][$week_num][0];
94. if(!empty($weeks[$real_year][$week_num][1]))
95. $end_day = $weeks[$real_year][$week_num][1];
96. }
97. $the_day = array(
98. 'begin_day' => $begin_day,
99. 'end_day' => $end_day
100. );
101. $the_day = json_encode($the_day);
102. return $the_day;
103. }
104. //demo_调用
105. /*
106. $day = '2014-01-01';
107. if(get_day_week($day)){
108. var_dump(get_day_week($day));
109. }else{
110. echo '日期格式出错';
111. }
112. */

复制代码