Date and time in PHP_PHP tutorial

PHP has many easy-to-use functions for displaying and processing dates.
To display date or time in a specific format, use the date() function. It takes two parameters: the format in which the date should be displayed and the timestamp representing the date you want to display. This timestamp must be the total number of seconds since 1970 as mentioned earlier (if you want to use the current time, use the time() function, which returns the "now" timestamp). date() has many formatting options, just like the strftime() function in C or the POSIX::strftime() function in Perl.
$birthday_stamp = mktime(19,45,0,3,10,1975);
$birthday_formatted = date('F d, Y - g:ia',$birthday_stamp) ;
echo "David was born on $birthday_formatted."
?>
will display
David was born on March 10, 1975--7:45 p.m.
Of course, if you need This complex formatting function is not very useful for a known specific date. Because you already know in advance what your format will be. These functions are useful when dealing with form output that requires the user to select a date:

$d = time();
for ($i = 0; $i < 10; $i++) {
echo ''.date('F d',$ d);
$d += 86400;
}
?>

The above will output a radio button with ten options - today and The next nine days. Before the program loop starts, we store the current time in the variable $d. Each value will be displayed, and the value will be calculated as a Unix timestamp, and the displayed text will be set to the month and day ("July 27", "July 28", etc.). After displaying the value, the variable $d will be incremented by 86,400 (which is the total number of seconds in a twenty-four-hour day - 24 hours * 60 minutes * 60 seconds).
By combining the mktime() and date() functions, you can get relevant information about the date entered by a specific user. What if you want to find the first Sunday (or any day of the week) starting from a specific date? First, write a function that will output the appropriate format:
functiondisplay_form() {
global $PHP_SELF;
$dotw = array('Sunday','Monday',' Tuesday','Wednesday','Thursday',
'Friday','Saturday');
$months = array( 1 => 'January','February','March','April' ,'May','June',
'July','August','September','October','November','December');
?>

Find the first

for ($ i = 0; $i < 7; $i++) {
echo " $dotw[$i]";
}
echo ' after ';
for ($i = 1; $i <= 12; $i++) {
echo " $months[$i ]";
}
echo ' ';
for ($i = 1; $i <= 31; $i++) {
echo " $i";
}
echo ', ';
$start_year = date('Y ') - 10;
$end_year = $start_year + 20;
for ($i = $start_year; $i <= $end_year; $i++) {
echo " $i ";
}
echo '';
echo '

';
}
?>
This contains some functions that we have not discussed so far. The $months array is written slightly differently because we need to index January as 1 instead of 0. In addition, it is easier to have this form automatically generated by a program than to manually list the values ​​​​of all the form elements. Therefore, the top part of the form is the only part of the display_form() function that does not belong to PHP mode. In addition, using data ("Y") to set the variable $start_year and the variable $end_year can conveniently handle the time range of ten years from this year.
The following is the function to process the form:
function process_form() {
global $dotw;
global $month;
global $day;
global $year;
$timestamp = mktime(0,0,0,$month,$day,$year);
$next_dotw = '';
$next_timestamp = $timestamp;
while ( $next_dotw != $dotw) {
$next_timestamp += 86400;
$next_dotw = date('l',$next_timestamp);
}
$formatted_first = date('F d, Y ',$timestamp);
$formatted_next = date('F d, Y',$next_timestamp);
echo "The first $dotw after $formatted_first is $formatted_next.";
}
?>
First, this code converts the resulting date into Unix timestamp form. If we needed to be more cautious, we could add some code to ensure that the resulting date falls within a legal date range, but we don't need to do that here.
When the week number of the "next day" we are looking for is not a week number entered by the user, the loop continues. When they are different, the total number of seconds represented by the date is incremented (also 86400 seconds = 24 hours * 60 minutes * 60 seconds), and then the number of weeks represented by that number of seconds is recalculated.
Once the week numbers match, the process_form() function will output a line of correct message:
The first Sunday after June 25, 1999 is June 27, 1999.
We also need the familiar main loop to convert these Functions are bundled together:
if (empty($stage)) { display_form(); }
else { process_form(); }
?>
Date processing The code sometimes needs to be more complex to handle daylight saving time and different time zones, but the date() and mktime() functions are basic tools for handling Unix timestamp conversions. They are algorithmically simple and intuitively express dates and times. The functions date() and mktime() operate on time based on the time zone of the machine. If you want to use Greenwich Mean Time (GMT), you can use the functions gmdate() and gmmktime().
For example, for a computer in Eastern Daylight Time (four hours behind GMT):
$today = mktime(12,0,0,6,25, 1999);
echo 'Here it is '.date('g:i:s a, F d, Y',$today);
echo '';
echo 'In GMT it is ' .gmdate('g:i:s a, F d, Y',$today);
?>
will display
Here it is 12:00:00 pm, June 25, 1999
In GMT it is 4:00:00 pm, June 25, 1999

http://www.bkjia.com/PHPjc/317075.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/317075.htmlTechArticlePHP has many easy-to-use functions for displaying and processing dates. To display a date or time in a specific format, use the date() function. It has two parameters: How to display the date in a format...