PHP Tips

Magic constants

似乎有許多"魔術"設計在 PHP 裡

__FILE__ : /path/to/file

__DIR__ : /path/to

__FUNCTION__ : 一般 namespace\function_name；類別中 function_name

__CLASS__ : 帶 NAMESPACE；namespace\class_name

__METHOD__ : 帶 NAMESPACE；namespace\class_name::function_name

__LINE__ : (int) 55

__NAMESPACE__ : namespace

// JSON
header('Content-Type: application/json; charset=utf-8');
// XML
header('Content-type: text/xml');

難怪我之前寫 ajax 需要手動 parseJSON ...

來源

PHP Timezone List

print_r(DateTimeZone::listIdentifiers(DateTimeZone::ALL));

$timezones = array(
    'Pacific/Midway'       => "(GMT-11:00) Midway Island",
    'US/Samoa'             => "(GMT-11:00) Samoa",
    'US/Hawaii'            => "(GMT-10:00) Hawaii",
    'US/Alaska'            => "(GMT-09:00) Alaska",
    'US/Pacific'           => "(GMT-08:00) Pacific Time (US &amp; Canada)",
    'America/Tijuana'      => "(GMT-08:00) Tijuana",
    'US/Arizona'           => "(GMT-07:00) Arizona",
    'US/Mountain'          => "(GMT-07:00) Mountain Time (US &amp; Canada)",
    'America/Chihuahua'    => "(GMT-07:00) Chihuahua",
    'America/Mazatlan'     => "(GMT-07:00) Mazatlan",
    'America/Mexico_City'  => "(GMT-06:00) Mexico City",
    'America/Monterrey'    => "(GMT-06:00) Monterrey",
    'Canada/Saskatchewan'  => "(GMT-06:00) Saskatchewan",
    'US/Central'           => "(GMT-06:00) Central Time (US &amp; Canada)",
    'US/Eastern'           => "(GMT-05:00) Eastern Time (US &amp; Canada)",
    'US/East-Indiana'      => "(GMT-05:00) Indiana (East)",
    'America/Bogota'       => "(GMT-05:00) Bogota",
    'America/Lima'         => "(GMT-05:00) Lima",
    'America/Caracas'      => "(GMT-04:30) Caracas",
    'Canada/Atlantic'      => "(GMT-04:00) Atlantic Time (Canada)",
    'America/La_Paz'       => "(GMT-04:00) La Paz",
    'America/Santiago'     => "(GMT-04:00) Santiago",
    'Canada/Newfoundland'  => "(GMT-03:30) Newfoundland",
    'America/Buenos_Aires' => "(GMT-03:00) Buenos Aires",
    'Greenland'            => "(GMT-03:00) Greenland",
    'Atlantic/Stanley'     => "(GMT-02:00) Stanley",
    'Atlantic/Azores'      => "(GMT-01:00) Azores",
    'Atlantic/Cape_Verde'  => "(GMT-01:00) Cape Verde Is.",
    'Africa/Casablanca'    => "(GMT) Casablanca",
    'Europe/Dublin'        => "(GMT) Dublin",
    'Europe/Lisbon'        => "(GMT) Lisbon",
    'Europe/London'        => "(GMT) London",
    'Africa/Monrovia'      => "(GMT) Monrovia",
    'Europe/Amsterdam'     => "(GMT+01:00) Amsterdam",
    'Europe/Belgrade'      => "(GMT+01:00) Belgrade",
    'Europe/Berlin'        => "(GMT+01:00) Berlin",
    'Europe/Bratislava'    => "(GMT+01:00) Bratislava",
    'Europe/Brussels'      => "(GMT+01:00) Brussels",
    'Europe/Budapest'      => "(GMT+01:00) Budapest",
    'Europe/Copenhagen'    => "(GMT+01:00) Copenhagen",
    'Europe/Ljubljana'     => "(GMT+01:00) Ljubljana",
    'Europe/Madrid'        => "(GMT+01:00) Madrid",
    'Europe/Paris'         => "(GMT+01:00) Paris",
    'Europe/Prague'        => "(GMT+01:00) Prague",
    'Europe/Rome'          => "(GMT+01:00) Rome",
    'Europe/Sarajevo'      => "(GMT+01:00) Sarajevo",
    'Europe/Skopje'        => "(GMT+01:00) Skopje",
    'Europe/Stockholm'     => "(GMT+01:00) Stockholm",
    'Europe/Vienna'        => "(GMT+01:00) Vienna",
    'Europe/Warsaw'        => "(GMT+01:00) Warsaw",
    'Europe/Zagreb'        => "(GMT+01:00) Zagreb",
    'Europe/Athens'        => "(GMT+02:00) Athens",
    'Europe/Bucharest'     => "(GMT+02:00) Bucharest",
    'Africa/Cairo'         => "(GMT+02:00) Cairo",
    'Africa/Harare'        => "(GMT+02:00) Harare",
    'Europe/Helsinki'      => "(GMT+02:00) Helsinki",
    'Europe/Istanbul'      => "(GMT+02:00) Istanbul",
    'Asia/Jerusalem'       => "(GMT+02:00) Jerusalem",
    'Europe/Kiev'          => "(GMT+02:00) Kyiv",
    'Europe/Minsk'         => "(GMT+02:00) Minsk",
    'Europe/Riga'          => "(GMT+02:00) Riga",
    'Europe/Sofia'         => "(GMT+02:00) Sofia",
    'Europe/Tallinn'       => "(GMT+02:00) Tallinn",
    'Europe/Vilnius'       => "(GMT+02:00) Vilnius",
    'Asia/Baghdad'         => "(GMT+03:00) Baghdad",
    'Asia/Kuwait'          => "(GMT+03:00) Kuwait",
    'Africa/Nairobi'       => "(GMT+03:00) Nairobi",
    'Asia/Riyadh'          => "(GMT+03:00) Riyadh",
    'Europe/Moscow'        => "(GMT+03:00) Moscow",
    'Asia/Tehran'          => "(GMT+03:30) Tehran",
    'Asia/Baku'            => "(GMT+04:00) Baku",
    'Europe/Volgograd'     => "(GMT+04:00) Volgograd",
    'Asia/Muscat'          => "(GMT+04:00) Muscat",
    'Asia/Tbilisi'         => "(GMT+04:00) Tbilisi",
    'Asia/Yerevan'         => "(GMT+04:00) Yerevan",
    'Asia/Kabul'           => "(GMT+04:30) Kabul",
    'Asia/Karachi'         => "(GMT+05:00) Karachi",
    'Asia/Tashkent'        => "(GMT+05:00) Tashkent",
    'Asia/Kolkata'         => "(GMT+05:30) Kolkata",
    'Asia/Kathmandu'       => "(GMT+05:45) Kathmandu",
    'Asia/Yekaterinburg'   => "(GMT+06:00) Ekaterinburg",
    'Asia/Almaty'          => "(GMT+06:00) Almaty",
    'Asia/Dhaka'           => "(GMT+06:00) Dhaka",
    'Asia/Novosibirsk'     => "(GMT+07:00) Novosibirsk",
    'Asia/Bangkok'         => "(GMT+07:00) Bangkok",
    'Asia/Jakarta'         => "(GMT+07:00) Jakarta",
    'Asia/Krasnoyarsk'     => "(GMT+08:00) Krasnoyarsk",
    'Asia/Chongqing'       => "(GMT+08:00) Chongqing",
    'Asia/Hong_Kong'       => "(GMT+08:00) Hong Kong",
    'Asia/Kuala_Lumpur'    => "(GMT+08:00) Kuala Lumpur",
    'Australia/Perth'      => "(GMT+08:00) Perth",
    'Asia/Singapore'       => "(GMT+08:00) Singapore",
    'Asia/Taipei'          => "(GMT+08:00) Taipei",
    'Asia/Ulaanbaatar'     => "(GMT+08:00) Ulaan Bataar",
    'Asia/Urumqi'          => "(GMT+08:00) Urumqi",
    'Asia/Irkutsk'         => "(GMT+09:00) Irkutsk",
    'Asia/Seoul'           => "(GMT+09:00) Seoul",
    'Asia/Tokyo'           => "(GMT+09:00) Tokyo",
    'Australia/Adelaide'   => "(GMT+09:30) Adelaide",
    'Australia/Darwin'     => "(GMT+09:30) Darwin",
    'Asia/Yakutsk'         => "(GMT+10:00) Yakutsk",
    'Australia/Brisbane'   => "(GMT+10:00) Brisbane",
    'Australia/Canberra'   => "(GMT+10:00) Canberra",
    'Pacific/Guam'         => "(GMT+10:00) Guam",
    'Australia/Hobart'     => "(GMT+10:00) Hobart",
    'Australia/Melbourne'  => "(GMT+10:00) Melbourne",
    'Pacific/Port_Moresby' => "(GMT+10:00) Port Moresby",
    'Australia/Sydney'     => "(GMT+10:00) Sydney",
    'Asia/Vladivostok'     => "(GMT+11:00) Vladivostok",
    'Asia/Magadan'         => "(GMT+12:00) Magadan",
    'Pacific/Auckland'     => "(GMT+12:00) Auckland",
    'Pacific/Fiji'         => "(GMT+12:00) Fiji",
);

判斷是否為 CLI 模式

// method 1
if (PHP_SAPI != "cli") die('not cli mode');
// method 2
if ( isset($_SERVER['argc']) && $_SERVER['argc']>=1 ) die('is cli mode');

PHP Closure

深入探討 PHP 5.3 的 Closure 觀念與用法

PHP external call

PHP 執行系統外部命令: system() exec() passthru() 與反撇號法

PHP micro timestamp to date

毫秒部分要獨立處理

// Target: Y-m-d h:i:s.u
$microtime = 1512464879000;
// sol 1
$time_converter = function($microtime) {
    return date('Y-m-d h:i:s.u', substr($microtime, 0, -3)) . '.' . substr($microtime, -3);
}
// sol 2
$time_converter = function($microtime, $tz = true) {
      $datetime = \DateTime::createFromFormat('U.u', number_format($microtime*0.001, 6, '.', ''))
;f      if($tz) $datetime->setTimezone(new \DateTimeZone('Asia/Taipei'));
      return $datetime;
  };

PHP self 與 static

PHP 的 static 與 self 兩個關鍵字的差異

Class A {
    public static function get_self() {
        return new self();
    }

    public static function get_static() {
        return new static();
    }
}

class B extends A {}

echo get_class(B::get_self());   // return A
echo get_class(B::get_static()); // return B
echo get_class(A::get_static()); // return A

推算離最近時間最近的開獎日

demo with sandbox

<?php
date_default_timezone_set("Asia/Taipei");
$time = time();
// echo $time, "\n", date('D', $time),"\n";
// echo date('r', 0), "\n";
// 時間戳 0 為星期四

$period = [1 => 'Fri', 2 => 'Sat', 3 => 'Sun', 4 => 'Mon', 5 => 'Tue', 6 => 'Wed', 7 => 'Thu'];
$days = ['Tue', 'Thu', 'Sat'];

function getClosetTimestamp ($days, $timestamp) {
    $day = date('D', $timestamp);
    if(in_array($day, $days)) $closetTimestamp = $timestamp;
    else {
       echo $timestamp = strtotime(date('Y-m-d', $timestamp)) + 86400, "\n";
       $closetTimestamp = getClosetTimestamp($days, $timestamp);
    }

    return $closetTimestamp;
}

// 測試推算開獎日
foreach (array_keys($period) as $multiply) {

    $timestamp = $time + 86400 * $multiply;
    echo "乘數為 $multiply, 投注時間為 " . date('Y-m-d, D', $timestamp), "\n";
    $resultTime =  getClosetTimestamp($days,  $timestamp);
    echo "開獎日為 " . date('Y-m-d 21:35:00, D', $resultTime), "\n";
}

浮點數比對陷阱

不只 PHP，其他語言的浮點數比對也要注意；原因是精確度的關係；小數存放是差分器的方法

Tips

PHP Tips

Magic constants

回傳 data 時記得送 header

PHP Timezone List

判斷是否為 CLI 模式

PHP Closure

PHP external call

PHP micro timestamp to date

PHP self 與 static

推算離最近時間最近的開獎日

浮點數比對陷阱

整理一下解法

刪除多餘的字元

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