Obtain the start date of the week based on the given date format & apos; YYYY-mm-dd & apos;

Obtain the start date of the week based on the given date format & amp; apos; YYYY-mm-dd & amp; apos;

Common Date Operations /** * Get the start date of all weeks in a year * @ Param $ year format 'yyyy' * Returns the two-dimensional array subscript key1 value corresponding to the actual year key2 value of the week of a day in a year corresponding to the number of weeks of a day in a year [week of a year] * Return false date format error */ Function get_all_weeks ($ year ){ $ Week_arr = array (); $ Year = intval (trim ($ year )); $ Preg = "/^ \ d {4,} $ /"; If (! Preg_match ($ preg, $ year )){ Return false; } $ Begin_day = $ year. '-01-01 '; $ End_day = $ year. '-12-31 '; // The first Monday of the year If (date ('W', strtotime ($ begin_day ))! = 1 ){ $ Begin_day = date ('Y-m-D', strtotime ("next Monday", strtotime ($ begin_day ))); } // Week number of the first Monday $ Begin_week_num = intval (date ('W', strtotime ($ begin_day ))); // Last Sunday of the year If (date ('W', strtotime ($ end_day ))! = 0 ){ $ End_day = date ('Y-m-D', strtotime ("last Sunday", strtotime ($ end_day ))); // There is a week of the new year, and the week and Monday of the new year $ End_day_next = date ('Y-m-D', strtotime ($ end_day) + 24*60*60 ); // Year and number of weeks of the cross-year week $ Stride_year = date ('O', strtotime ($ end_day_next )); $ Stride_weeknum = intval (date ('W', strtotime ($ end_day_next ))); } // Week number of the last Sunday $ End_week_num = intval (date ('W', strtotime ($ end_day ))); // The first Monday of a year is the first or second week of a year. If ($ begin_week_num! = 1 ){ $ I = 2; } Else { $ I = 1; } $ J = 0; For ($ I; $ I <= $ end_week_num; $ I ++ ){ $ Start_date = date ("Y-m-d", strtotime ("$ begin_day $ j week ")); $ End_day = date ("Y-m-d", strtotime ($ start_date. '+ 6 Day ')); $ Week_arr [$ year] [$ I] = array ( $ Start_date, $ End_day ); $ J ++; } If ($ end_day_next ){ $ Week_arr [$ stride_year] [$ stride_weeknum] = array ( $ End_day_next, Date ("Y-m-d", strtotime ($ end_day_next. '+ 6 Day ')) ); } Return $ week_arr; } // Demo _ call /* $ Year = '000000 '; If (get_all_weeks ($ year )){ Var_dump (get_all_weeks ($ year )); } Else { Echo 'date format error '; } */ /** * Obtain the start date of the week in which a day is located. * Dependent function get_all_weeks * @ Param $ day format: 'yyyy-mm-DD' * Return false date format error * Correct. json "{" begin_day ":" YYYY-mm-dd "," end_day ":" YYYY-mm-dd "}" is returned "}" */ Function get_day_week ($ day ){ $ Date_arr = explode ('-', trim ($ day )); If (! Checkdate (intval ($ date_arr [1]), intval ($ date_arr [2]), intval ($ date_arr [0]) { Return false; } $ Year = date ('Y', strtotime ($ day )); $ Weeks = get_all_weeks ($ year ); // Year and week of a day $ Real_year = date ('O', strtotime ($ day )); $ Week_num = intval (date ('W', strtotime ($ day ))); If (! Empty ($ weeks [$ real_year] [$ week_num] [0]) $ Begin_day = $ weeks [$ real_year] [$ week_num] [0]; If (! Empty ($ weeks [$ real_year] [$ week_num] [1]) $ End_day = $ weeks [$ real_year] [$ week_num] [1]; // The cross-year week value is stored in the previous year If (empty ($ begin_day) | empty ($ end_day )){ $ Year = date ('Y', strtotime ($ day)-1; $ Weeks = get_all_weeks ($ year ); $ Real_year = date ('O', strtotime ($ day )); $ Week_num = intval (date ('W', strtotime ($ day ))); If (! Empty ($ weeks [$ real_year] [$ week_num] [0]) $ Begin_day = $ weeks [$ real_year] [$ week_num] [0]; If (! Empty ($ weeks [$ real_year] [$ week_num] [1]) $ End_day = $ weeks [$ real_year] [$ week_num] [1]; } $ The_day = array ( 'Begin_day' => $ begin_day, 'End _ day' => $ end_day ); $ The_day = json_encode ($ the_day ); Return $ the_day; } // Demo _ call /* $ Day = '2017-01-01 '; If (get_day_week ($ day )){ Var_dump (get_day_week ($ day )); } Else { Echo 'date format error '; } */