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- Working with DateTime 4:21
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- DateTime Comparisons 3 questions
- Understanding Time Zones 3:56
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- Understanding UTF-8 3 questions
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Working with DateTime
4:21Dates and times in PHP used to be quite a mess in the PHP 4 days, but the DateTime class has brought much easier workflows.
PHP has a code class called Date Time.
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This will help you in reading, writing,
comparing dates, or
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making date time related calculations.
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There are many date and
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time related functions in PHP besides the
date time class, but
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this provides a nice object oriented
interface to most of the common uses.
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So let’s start off by opening index dot
PHP.
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On line three, we’re going to create a new
date time object and
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store it in the date variable.
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In this case,
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we'll be creating a object by passing a
string into the class constructor.
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This string will contain a date, which can
be in one of a bunch of different formats.
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We'll look at some of these formats
shortly, but for
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now, this example has an input format of
year, comma, August 23.
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On line seven we're outputting a paragraph
of the text.
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The output day is, then using the format
method on
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our date time object output the date in
our own specific format.
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Our example here use M slash D slash
capital Y is an output format.
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Meaning when we run this script we should
expect to see 08/23/2014.
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Let's take a look in preview mode, by
clicking on the eye icon.
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Cool, that works.
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Here we have the output date is
08/23/2014, just like we expected.
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The benefit here is that we can change the
input date string, and
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have the same output format.
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One alternative commonly used input
format, is the SQL date string.
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Let's go back to the work space.
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Back to index.php and let's enter a new
date and a new format.
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So I'm gonna keep the year 2014.
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I'm gonna change things around a little
bit and enter 09-12.
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Which is the 12th of September.
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I save that out.
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Then refresh.
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Great, we have the exact same date format,
but it has a different date.
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If we go out back to the workspace, we can
get a little bit more adventurous with
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initializing date time objects using
string offsets.
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We can change the constructor to take a
string starting with a plus or a minus.
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Then we add number of units and
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define the unit with the words second,
hours, days, weeks, months, or even years.
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So if we enter plus two weeks and have a
little look, see what happens there.
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Then we will have an output which is two
weeks from now.
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Brilliant.
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You can jump forwards using more
human-friendly phrases, too.
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We can change this string to contain
phrases like next week or tomorrow.
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So let's have a go at that.
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Next week.
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Perfect.
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Tomorrow.
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There we go.
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As I mentioned earlier the string argument
passed to the date time constructor on
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line three can accept dates in many
different input formats.
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To learn more about the date time formats
we can use the PHP manual.
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There is a link in the notes for
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this video called PHP date formats so
let's head over there.
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[SOUND] You scroll about half way down.
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You can see under localized notations
there's a whole bunch of
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different formats supported.
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Some American ones.
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Some more generic.
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The format here.
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This is a literal string.
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So that means it's actually a slash, and
not some special meaning.
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And then you can see some actual examples
of how they look.
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So, when you use them they'll come out
without the quotation marks around them.
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And there's some other fairly common
formats here.
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This one, like the four digit year, month,
and
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day with slashes could be one that you
might want to use.
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Sometimes you will need to work with dates
that are stored in unsupported formats,
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for example if a string contains two date
segments with numeric values below 13 they
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could both be days or months.
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Luckily the date time class has a method
called create from format we can
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provide our custom input format to this
method along with our date so
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that PHP can read the string correctly.
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If we go back to our workspace, paste this
code in.
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On line three here we have a string
containing an unsupported date format.
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We store it in the raw variable and pass
it to the create from format method.
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If all goes well,
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when we run this once again, we should see
our date output in the same format.
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This time the date should be 11/10/1968.
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Save that and see if it works.
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Perfect!
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Let's move on.
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