PHP Date Function

The PHP date() function is used to format a time and/or date.

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The PHP Date() Function

The PHP date() function formats a timestamp to a more readable date and time.
 A timestamp is a sequence of characters, denoting the date and/or time at which a certain event occurred.

Syntax

date(format,timestamp)

Parameter	Description
format	Required. Specifies the format of the timestamp
timestamp	Optional. Specifies a timestamp. Default is the current date and time

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PHP Date() - Format the Date

The required format parameter in the date() function specifies how to format the date/time.
Here are some characters that can be used:

• d - Represents the day of the month (01 to 31)
• m - Represents a month (01 to 12)
• Y - Represents a year (in four digits)

A list of all the characters that can be used in the format parameter, can be found in our PHP Date reference.
Other characters, like"/", ".", or "-" can also be inserted between the letters to add additional formatting:

echo date("Y/m/d") . "
";
echo date("Y.m.d") . "
";
echo date("Y-m-d");
?>

The output of the code above could be something like this:

2009/05/11
2009.05.11
2009-05-11

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PHP Date() - Adding a Timestamp

The optional timestamp parameter in the date() function specifies a timestamp. If you do not specify a timestamp, the current date and time will be used.
The mktime() function returns the Unix timestamp for a date.
The Unix timestamp contains the number of seconds between the Unix Epoch (January 1 1970 00:00:00 GMT) and the time specified.

Syntax for mktime()

mktime(hour,minute,second,month,day,year,is_dst)

To go one day in the future we simply add one to the day argument of mktime():

$tomorrow = mktime(0,0,0,date("m"),date("d")+1,date("Y"));
echo "Tomorrow is ".date("Y/m/d", $tomorrow);
?>

The output of the code above could be something like this:

Tomorrow is 2009/05/12

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Complete PHP Date Reference

For a complete reference of all date functions, go to our complete PHP Date Reference.
The reference contains a brief description, and examples of use, for each function!

PHP Functions

A function is something that performs a specific task. People write functions if they plan on doing the same task over and over again. This allows you to only write the code once and save a lot of time and space.

Although in the next few pages we will lean how to write our own functions, PHP has several functions that already exist for us to use. Although they all have different uses, all functions are phrased as: name(argument). The name being the name of the function, and the argument being the value(s) it is using.

Here are some examples of functions already in PHP:

 "; 
 print "The square root of 16 is " . $b . "
"; 
 print "12.3 rounded is " . $c . " and 12.5 rounded is " . round(12.5); 
 ?> 

This gives an example of three functions; absolute value, square root, and rounding. As you can see you can use the function right in the print statement or you can assign it to a variable. A list of functions can be found here.