Add date offset to current code

[Brian_15]

How do improve this class to output offset like + 02:00,  - 02:00

What i want to achieve is this output: [ UTC/GMT - 11:00 ] - Timezone name

class Time_zone {
	
    private $regions = array(
        'Africa' => DateTimeZone::AFRICA,
        'America' => DateTimeZone::AMERICA,
	'Antarctica' => DateTimeZone::ANTARCTICA,
	'Artic' => DateTimeZone::ARCTIC,
	'Asia' => DateTimeZone::ASIA,
	'Atlantic' => DateTimeZone::ATLANTIC,
	'Australia' => DateTimeZone::AUSTRALIA,
	'Europe' => DateTimeZone::EUROPE,
	'Indian' => DateTimeZone::INDIAN,
	'Pacific' => DateTimeZone::PACIFIC
    );
	
    public function generate_list() {
		
	$time_zones  = array();
	foreach ($this->regions as $name => $mask) {
	    $time_zones[$name] = DateTimeZone::listIdentifiers($mask);
	}
		
	return $time_zones;

    }
	
}

$tz = new Time_zone();
?>
<pre><?=print_r($tz->generate_list());?></pre>

[requinix]

Your generate_list() will return an array of arrays. Loop over those to get timezone identifiers, construct a DateTimeZone for each, then use its getOffset() method with some quick math (to convert seconds to hours+minutes) to form that output.

[Barand]

Create a dateTime object for each timezone. Format the time with 'P' format.

class Time_zone {
    
    private $regions = array(
        'Africa' => DateTimeZone::AFRICA,
        'America' => DateTimeZone::AMERICA,
    'Antarctica' => DateTimeZone::ANTARCTICA,
    'Artic' => DateTimeZone::ARCTIC,
    'Asia' => DateTimeZone::ASIA,
    'Atlantic' => DateTimeZone::ATLANTIC,
    'Australia' => DateTimeZone::AUSTRALIA,
    'Europe' => DateTimeZone::EUROPE,
    'Indian' => DateTimeZone::INDIAN,
    'Pacific' => DateTimeZone::PACIFIC
    );
    
    public function generate_list() {
        
    $time_zones  = array();
    foreach ($this->regions as $name => $mask) {
        $time_zones[$name] = DateTimeZone::listIdentifiers($mask);
    }
    
    foreach ($time_zones as &$zones) {
        foreach ($zones as &$zstr) {
            $zn = new DateTimeZone($zstr);
            $t = new DateTime('now', $zn);
            $offset = $t->format('P');
            $zstr = "[UTC/GMT $offset] $zstr";
        }
    }    
    return $time_zones;

    }
    
}

[Brian_15]

Testing code

$time_zone = new Time_zone();
?>

<select>
<?php foreach($time_zone->generate_list() as $region => $list) { ?>
  <optgroup label="<?=$region?>">
  <?php foreach($list as $name) { ?>
    <option value="<?=$name?>"><?=$name?></option>
    <?php } ?>
  </optgroup>
  <?php } ?>
</select>

Current output

<option value="[UTC/GMT +00:00] Africa/Abidjan">[UTC/GMT +00:00] Africa/Abidjan</option>

Expected output

<option value="Africa/Abidjan">[UTC/GMT +00:00] Africa/Abidjan</option>

Edited July 26, 2016 by Brian_15

[Barand]

How do improve this class to output offset like + 02:00,  - 02:00

What i want to achieve is this output: [ UTC/GMT - 11:00 ] - Timezone name

What you are now asking for is not what you originally asked for. I am not getting involved in an ever-escalating spiral of requirements (Not for free anyway).

 

Hint: make "Africa/Abidjan" the key of the returned array and "[uTC/GMT +00:00] Africa/Abidjan" the value then build your options using both.

[Brian_15]

Now its woking

<?php

class Time_zone {
    
    protected $regions = array(
        'Africa' => DateTimeZone::AFRICA,
        'America' => DateTimeZone::AMERICA,
    	'Antarctica' => DateTimeZone::ANTARCTICA,
    	'Artic' => DateTimeZone::ARCTIC,
    	'Asia' => DateTimeZone::ASIA,
    	'Atlantic' => DateTimeZone::ATLANTIC,
    	'Australia' => DateTimeZone::AUSTRALIA,
    	'Europe' => DateTimeZone::EUROPE,
    	'Indian' => DateTimeZone::INDIAN,
    	'Pacific' => DateTimeZone::PACIFIC
    );
    
    public function get_list() {
		
        $time_zones = array();
   	foreach ($this->regions as $name => $mask) {
			
	    foreach(DateTimeZone::listIdentifiers($mask) as $time_zone) {
	        $time_zones[$name][$time_zone] = '[UTC/GMT ' . $this->get_offset($time_zone) . '] ' . $time_zone;
	    }
			
	}
		
	return $time_zones;
		
    }
		
    protected function get_offset($time_zone) {
		
	$_tz = new DateTimeZone($time_zone);
        $_dt = new DateTime('now', $_tz);
        
        return $_dt->format('P');
		
    }
			
}

<?php
$time_zone = new Time_zone();
?>

<select>
<?php foreach($time_zone->get_list() as $region => $list) { ?>
    <optgroup label="<?=$region?>">
    <?php foreach($list as $time_zone => $name) { ?>
        <option value="<?=$time_zone?>"><?=$name?></option>
    <?php } ?>
    </optgroup>
<?php } ?>
</select> 

Output

<select>
    <optgroup label="Africa">
        <option value="Africa/Abidjan">[UTC/GMT +00:00] Africa/Abidjan</option>
	<option value="Africa/Accra">[UTC/GMT +00:00] Africa/Accra</option>
                         ...................................
    </optgroup>
    <optgroup label="America">
        <option value="America/Adak">[UTC/GMT -09:00] America/Adak</option>
	<option value="America/Anchorage">[UTC/GMT -08:00] America/Anchorage</option>
                         ...................................

Edited July 28, 2016 by Brian_15