//这个星期的星期一// @$timestamp ，某个星期的某一个时间戳，默认为当前时间// @is_return_timestamp ,是否返回时间戳，否则返回时间格式function this_monday($timestamp=0,$is_return_timestamp=true){static $cache ;$id = $timestamp.$is_return_timestamp;if(!isset($cache[$id])){if(!$timestamp) $timestamp = time();$monday_date = date('Y-m-d', $timestamp-86400*date('w',$timestamp)+(date('w',$timestamp)>0?86400:-/*6*86400*/518400));if($is_return_timestamp){$cache[$id] = strtotime($monday_date);}else{$cache[$id] = $monday_date;}}return $cache[$id];}//这个星期的星期天// @$timestamp ，某个星期的某一个时间戳，默认为当前时间// @is_return_timestamp ,是否返回时间戳，否则返回时间格式function this_sunday($timestamp=0,$is_return_timestamp=true){static $cache ;$id = $timestamp.$is_return_timestamp;if(!isset($cache[$id])){if(!$timestamp) $timestamp = time();$sunday = this_monday($timestamp) + /*6*86400*/518400;if($is_return_timestamp){$cache[$id] = $sunday;}else{$cache[$id] = date('Y-m-d',$sunday);}}return $cache[$id];}//上周一// @$timestamp ，某个星期的某一个时间戳，默认为当前时间// @is_return_timestamp ,是否返回时间戳，否则返回时间格式function last_monday($timestamp=0,$is_return_timestamp=true){static $cache ;$id = $timestamp.$is_return_timestamp;if(!isset($cache[$id])){if(!$timestamp) $timestamp = time();$thismonday = this_monday($timestamp) - /*7*86400*/604800;if($is_return_timestamp){$cache[$id] = $thismonday;}else{$cache[$id] = date('Y-m-d',$thismonday);}}return $cache[$id];}//上个星期天// @$timestamp ，某个星期的某一个时间戳，默认为当前时间// @is_return_timestamp ,是否返回时间戳，否则返回时间格式function last_sunday($timestamp=0,$is_return_timestamp=true){static $cache ;$id = $timestamp.$is_return_timestamp;if(!isset($cache[$id])){if(!$timestamp) $timestamp = time();$thissunday = this_sunday($timestamp) - /*7*86400*/604800;if($is_return_timestamp){$cache[$id] = $thissunday;}else{$cache[$id] = date('Y-m-d',$thissunday);}}return $cache[$id];}//这个月的第一天// @$timestamp ，某个月的某一个时间戳，默认为当前时间// @is_return_timestamp ,是否返回时间戳，否则返回时间格式function month_firstday($timestamp = 0, $is_return_timestamp=true){static $cache ;$id = $timestamp.$is_return_timestamp;if(!isset($cache[$id])){if(!$timestamp) $timestamp = time();$firstday = date('Y-m-d', mktime(0,0,0,date('m',$timestamp),1,date('Y',$timestamp)));if($is_return_timestamp){$cache[$id] = strtotime($firstday);}else{$cache[$id] = $firstday;}}return $cache[$id];}//这个月的第一天// @$timestamp ，某个月的某一个时间戳，默认为当前时间// @is_return_timestamp ,是否返回时间戳，否则返回时间格式function month_lastday($timestamp = 0, $is_return_timestamp=true){static $cache ;$id = $timestamp.$is_return_timestamp;if(!isset($cache[$id])){if(!$timestamp) $timestamp = time();$lastday = date('Y-m-d', mktime(0,0,0,date('m',$timestamp),date('t',$timestamp),date('Y',$timestamp)));if($is_return_timestamp){$cache[$id] = strtotime($lastday);}else{$cache[$id] = $lastday;}}return $cache[$id];}//上个月的第一天// @$timestamp ，某个月的某一个时间戳，默认为当前时间// @is_return_timestamp ,是否返回时间戳，否则返回时间格式function lastmonth_firstday($timestamp = 0, $is_return_timestamp=true){static $cache ;$id = $timestamp.$is_return_timestamp;if(!isset($cache[$id])){if(!$timestamp) $timestamp = time();$firstday = date('Y-m-d', mktime(0,0,0,date('m',$timestamp)-1,1,date('Y',$timestamp)));if($is_return_timestamp){$cache[$id] = strtotime($firstday);}else{$cache[$id] = $firstday;}}return $cache[$id];}//上个月的第一天// @$timestamp ，某个月的某一个时间戳，默认为当前时间// @is_return_timestamp ,是否返回时间戳，否则返回时间格式function lastmonth_lastday($timestamp = 0, $is_return_timestamp=true){static $cache ;$id = $timestamp.$is_return_timestamp;if(!isset($cache[$id])){if(!$timestamp) $timestamp = time();$lastday = date('Y-m-d', mktime(0,0,0,date('m',$timestamp)-1, date('t',lastmonth_firstday($timestamp)),date('Y',$timestamp)));if($is_return_timestamp){$cache[$id] = strtotime($lastday);}else{$cache[$id] = $lastday;}}return $cache[$id];}echo '本周星期一：'.this_monday(0,false).'';echo '本周星期天：'.this_sunday(0,false).'';echo '上周星期一：'.last_monday(0,false).'';echo '上周星期天：'.last_sunday(0,false).'';echo '本月第一天：'.month_firstday(0,false).'';echo '本月最后一天：'.month_lastday(0,false).'';echo '上月第一天：'.lastmonth_firstday(0,false).'';echo '上月最后一天：'.lastmonth_lastday(0,false).'';
