Date Manipulation in Php Page 3

Changing the way the date is displayed – date and time formatting

PHP supplies you with 2 ways of turning the Unix timestamp into something useful.
The first one is a function called date(). This function takes two arguments – a
string that lays out the formatting that you want returned, the second the Unix timestamp.
The formatting string is simply some special characters that display those parts of
the date and time that you want in the format that you want it.
Suppose you wanted the date to be displayed as “18h01 Sunday 21 May”

We will need to use one of the special characters for each of the changing bits in the
string- you can look these up in the PHP manual under function.date.html. There’s a fair
number of these characters and they will return things like the day of the week, month
name, year in 2 and 4 digit format, whether it AM or PM and many others.
The ones that we will need for this example are:

‘H’	which returns the hour of the day in 24-hour format
‘i’	which will return the minutes
‘l’	which will return the day of the week (long form)
‘d’	which returns the day of the month and
‘F’	the full month name

So our string will look something like “Hhi l d F”, and our PHP a bit like:

<?php
echo date( 'Hhi l d F', time() );
?>

When we run this though, we find that we actually get the result of

180609 Sunday 21 May

which seems a bit curious until we have a look at the PHP manual and find that the lowercase
h stands for the hour in 12 hour format. So once again, the old saying of “A computer does
what you tell it to do, not what you want it to do” rings true. We have two options here.
The first is to escape the lowercase h and have this:

<?php
echo date( 'Hhi l d F', time() );
?>

which gives us the result:

18h12 Sunday 21 May

This is great, but what happens if we want to include some date and time info into a more
complicated sentence? Do we have to escape every character? No, we use a different
function, one called strftime().

strftime() brings with it 2 advantages. The first which we are not going to cover here is
that if you have used the setlocale() function, you can have strftime bring the month names
up in the correct language. The other advantage is that you can embed your specially
formatted date and time info into free-form strings. This does mean however that if you went
and learned all of the special characters for the date() function, you get to learn a whole
set of different ones now.

The way that strftime() works is exactly the same as date(), except that the special characters
have the percent sign % in front of them. So the previous example in strftime() would look like

<?php
echo strftime( '%Hh %M %A %d %b', time() );
?>

which gives us:

18h24 Sunday 21 May

This may seem a trifle more complicated, but imagine what you actually wanted to say was
“Today is Sunday 21 May 2000. The time is somewhere close to 18h24.”
Using the date command in this instance would be a bit annoying I think.

Earlier I mentioned that there were 2 ways of getting something useful out of the Unix
timestamp. We’ve just seen date() and strftime(). The other is getdate().
This function only needs the Unix timestamp as an argument and it returns an associative
array of the elements in the date.

As an example:

<?php
$date_time_array = getdate( time() );
echo $date_time_array['weekday'];
?>

will return:

Sunday

Besides “weekday”, the other parts of the array are:

“seconds”	seconds
“minutes”	minutes
“hours”	hours
“mday”	day of the month
“wday”	day of the week as a number
“mon”	month as a number
“year”	year
“yday”	day of the year as a number
“month”	full month name

So now we can create readable dates and times. But what about going the other way ?