[SOLVED] preg_match timestring

[RichardRotterdam]

I never used regular expressions much since i didnt found the need to really use it and there were always other ways to achieve the samething without using it. however in a lot of cases its quite usefull.

 

I'm trying to validate a string to see if it is a valid time.

 

the string should allow "00:00" to "24:00"

 

I have the following

<?php
$pattern ="/([0-2][0-9])+[0-5][0-9])$/";
if (preg_match($pattern, $time_val)) {
    echo("valid string");
}
?>

this works buttttttttttttttttttttttt.......

this also allows the value "99:00"

the minutes i think i have but the hours is trickier how can fix it so it allows the numbers till 24?

 

 

 

[JasonLewis]

Give this a shot:

$pattern ="/(([0-1]{1}[0-9]{1})|([2]{1}[0-4]{1}))[0-5]{1}[0-9]{1})$/";

[RichardRotterdam]

thanks that nearly worked

it still accepted 24:31 but i fixed that by

changing the 4 into a 3

 

result

<?php
$pattern ="/(([0-1]{1}[0-9]{1})|([2]{1}[0-3]{1}))[0-5]{1}[0-9]{1})$/";
if (preg_match($pattern, $time_val)) {
    echo("valid string");
}
?>

Other then having a solution i want to understand what it actually does.

some things that are unclear to me

1. does the pipeline"|" in the patternt mean OR?

2. what does {1} mean in the pattern

 

[thebadbad]

A bit late, but gonna post anyway

 

Aren't 00:00 and 24:00 the same moment (or 24 hours apart)? And you forgot a caret (^) at the start of the pattern. Also, it can be done simpler than ProjectFear's code (BTW, it also allows 24:59); all the {1}s aren't necessary.

 

00:00-24:00:

 

$pattern = '~^((([01]\d)|([2][0-3])):[0-5][0-9])|24:00$~D';

 

and 00:00-23:59:

 

$pattern = '~^(([01]\d)|([2][0-3])):[0-5][0-9]$~D';

 

Notes: Yes, the pipe means OR, and {1} means "exactly one of the previous character" ([0-9]{1} would be one digit between 0 and 9). But {1} isn't necessary, since a character class matches only one character, when nothing else is specified. You can also specify a range with e.g. {1,3} (between 1 and 3 characters).

[thebadbad]

To explain further, \d is equal to using [0-9].

(([01]\d)|([2][0-3])) matches either 00-19 or 20-23, thus not allowing 29:xx as an example.

^ matches the start of the string, and $ the end (i.e. we're validating the whole string, not parts of it).

The D modifier at the end of the pattern makes sure that $ matches the end of the string only, and not also a new line (read here).

[thebadbad]

BTW, http://www.regular-expressions.info/ is a great resource if you want to go further with learning regular expressions.

[RichardRotterdam]

thanks a bunge thats something i can work with