PHP CookBook

Recipe 3.2 Finding the Current Date and Time

3.2.1 Problem

You want to know what the time or date is.

3.2.2 Solution

Use strftime( ) or date( ) for a formatted time string:

print strftime('%c');
print date('r');
Mon Aug 12 18:23:45 2002
Mon, 12 Aug 2002 18:23:45 -0400

Use getdate( ) or localtime( ) if you want time parts:

$now_1 = getdate( );
$now_2 = localtime( );
print "$now_1[hours]:$now_1[minutes]:$now_1[seconds]";
print "$now_2[2]:$now_2[1]:$now_2[0]";
18:23:45
18:23:45

3.2.3 Discussion

The functions strftime( ) and date( ) can produce a variety of formatted time and date strings. They are discussed in more detail in Recipe 3.5. Both localtime( ) and getdate( ), on the other hand, return arrays whose elements are the different pieces of the specified date and time.

The associative array getdate( ) returns has the key/value pairs listed in Table 3-1.

Table 3-1. Return array from getdate( )

Key	Value
seconds	Seconds
minutes	Minutes
hours	Hours
mday	Day of the month
wday	Day of the week, numeric (Sunday is 0, Saturday is 6)
mon	Month, numeric
year	Year, numeric
yday	Day of the year, numeric (e.g., 299)
weekday	Day of the week, textual, full (e.g., "Friday")
month	Month, textual, full (e.g., "January")

For example, here's how to use getdate( ) to print out the month, day, and year:

$a = getdate( );
printf('%s %d, %d',$a['month'],$a['mday'],$a['year']);
August 7, 2002

Pass getdate( ) an epoch timestamp as an argument to make the returned array the appropriate values for local time at that timestamp. For example, the month, day, and year at epoch timestamp 163727100 is:

$a = getdate(163727100);
printf('%s %d, %d',$a['month'],$a['mday'],$a['year']);
March 10, 1975

The function localtime( ) returns an array of time and date parts. It also takes an epoch timestamp as an optional first argument, as well as a boolean as an optional second argument. If that second argument is true, localtime( ) returns an associative array instead of a numerically indexed array. The keys of that array are the same as the members of the tm_struct structure that the C function localtime( ) returns, as shown in Table 3-2.

Table 3-2. Return array from localtime( )

Numeric position	Key	Value
0	tm_sec	Second
1	tm_min	Minutes
2	tm_hour	Hour
3	tm_mday	Day of the month
4	tm_mon	Month of the year (January is 0)
5	tm_year	Years since 1900
6	tm_wday	Day of the week
7	tm_yday	Day of the year
8	tm_isdst	Is daylight saving time in effect?

For example, here's how to use localtime( ) to print out today's date in month/day/year format:

$a = localtime( );
$a[4] += 1;
$a[5] += 1900;
print "$a[4]/$a[3]/$a[5]";
8/7/2002

The month is incremented by 1 before printing since localtime( ) starts counting months with 0 for January, but we want to display 1 if the current month is January. Similarly, the year is incremented by 1900 because localtime( ) starts counting years with 0 for 1900.

Like getdate( ), localtime( ) accepts an epoch timestamp as an optional first argument to produce time parts for that timestamp:

$a = localtime(163727100);
$a[4] += 1;
$a[5] += 1900;
print "$a[4]/$a[3]/$a[5]";
3/10/1975

3.2.4 See Also

Documentation on strftime( ) at http://www.php.net/strftime, date( ) at http://www.php.net/date, getdate( ) at http://www.php.net/getdate, and localtime( ) at http://www.php.net/localtime.