PHP Take this week, the first day of the month and the last day

Echo ' The first day of the week (Sunday is the beginning of the week): '. Date (' y-m-d ', Time () -86400*date (' W ')). ' '; Echo ' The first day of the week (Monday is the beginning of the week): '. Date (' y-m-d ', Time () -86400*date (' W ') + (date (' W ') >0?86400:-6*86400). ' '; Echo ' first day of the month: '. Date (' y-m-d ', Mktime (0,0,0,date (' n '), 1,date (' Y ')). ' '; Echo ' Last day of the month: '. Date (' y-m-d ', Mktime (0,0,0,date (' n '), date (' t '), date (' Y ')). ' '; Copy Code 2,php DATE gets the first and last day of the month! echo Date (' y-m-01 ', Time ()). ' ----'. Date (' Y-m-t ', Time ()) 3,php time function The first day of the month on the first day of the given date Code: Function Getpurmonth ($date) {//Gets the first and last day of the previous month for the specified date. $time =strtotime ($date); $firstday =date (' y-m-01 ', strtotime (date (' Y ', $time). ' -'. (Date (' m ', $time)-1). ' -01 ')); $lastday =date (' y-m-d ', Strtotime ("$firstday +1 month-1 Day"); Return Array ($firstday, $lastday); } Copy Code The problem arises. For example get the first day, above this use (date (' m ', $time)-1); If you get a given date last month. Do you want to lose 2 directly? What if the given date is January? Will it eventually become date (' y-m-01 ', strtotime (' 2012--1-01 '))????? This is obviously a wrong time format. So this function is not suitable for extended use. Query PHP function library, find a function mktime (); Mktime () defines and uses the Mktime () function to return a Unix timestamp of a date. The parameter always represents the GMT date, so IS_DST has no effect on the result. Parameters can be left-to-right and empty, and empty parameters will be set to the corresponding current GMT value. Grammar Mktime (HOUR,MINUTE,SECOND,MONTH,DAY,YEAR,IS_DST) Example: the Mktime () function is useful for date arithmetic and validation. It can automatically correct out-of-bounds input, what does it mean. automatically corrects out-of-bounds input. Enemies. That's what we want. Below is a look at the example echo Date (' y-m-d ', strtotime (' 2012--2-1 ')); Echo ' '; echo Date (' y-m-d ', Mktime (0,0,0,-2,1,2012)); Copy Code The date 2 months before January 1, 2012 is to be output. That is October 1, 2011. 1970-01-012011-10-01 Conclusion: The first function has an error. Shows the time when the timestamp is 0. and the second function lets us get the time we want.

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