Regular expression and create substring for time - php

Question

I need a regular for time format HH:MM am/pm. I found something like
$time = "HH:MM am";
preg_match('/[\s0]*(\d|1[0-2]):(\d{2})\s*([AaPp][Mm])/xms', $time, $match);
$h = $match[1];
$m = $match[2];
$a = $match[3];
There are lot of regular expression for time. But what i am looking is if someone write aa:mn jk instead of number then it should give $h=aa $m=mn and $a=jk Or if someone keep them blank or partial filled like abcd then $h=abcd $m=null and $a=null.
I solved it using for loop and some if else but hope some can help me to do it using regular expression or using some PHP function.

Answer 1

You're going to need regexp like this ~^(\d{1,2})((?::)(\d{1,2}))?(\s+(am|pm))?$~i
The whole testing code would be:
<?php
$regexp = '~^(\d{1,2})((?::)(\d{1,2}))?(\s+(am|pm))?$~i';
$tests = array(
'18',
'18:00',
'7:03 pm',
'7 pm'
);
$match = array();
foreach( $tests as $test){
preg_match( $regexp, $test, $match);
print_r( $match);
}
And the results:
Array
(
[0] => 18
[1] => 18
)
Array
(
[0] => 18:00
[1] => 18
[2] => :00
[3] => 00
)
Array
(
[0] => 7:03 pm
[1] => 7
[2] => :03
[3] => 03
[4] => pm
[5] => pm
)
Array
(
[0] => 7 am
[1] => 7
[2] =>
[3] =>
[4] => am
[5] => am
)
So you can prepare you final output like:
$hours = isset( $match[1]) ? $match[1] : '00';
$minutes = isset( $match[3]) ? $match[3] : '00';
$am = isset( $match[5]) ? $match[5] : 'am';
If you need explanation of anything please ask in the comment

Answer 2

Using Regex might be a little overkill. Use the explode() function instead.
<?php
$str = 'aa:bb cc'; // or 'abcd'
$a = explode(':', $str);
$b = isset($a[1]) ? explode(' ', $a[1]) : NULL;
$h = $a[0];
$m = isset($b[0]) ? $b[0] : NULL;
$a = isset($b[1]) ? $b[1] : NULL;
var_dump($h, $m, $a);

Answer 3

You were very vague about your requirements, so I don't really know what you're trying to match, but this will match any number of non-: characters and stick it in $h, followed by an optional : and non-space characters which will be put in $m, followed by an optional 0 or more spaces and the remaining characters will be put in $a:
if (!preg_match('/^([^:]+)(:(\S+))?(\s*(.+))?$/i', $input, $matches)) {
// pattern did not match
}
$h = $matches[1];
$m = $matches[3] ?: NULL;
$a = $matches[5] ?: NULL;