問題描述
我會試著解釋這里的問題.
I'll try to explain what's the problem here.
根據 PHP 手冊中的支持的時區列表，我可以在 PHP 中看到所有有效的 TZ 標識符.
According to list of supported timezones from PHP manual, I can see all valid TZ identifiers in PHP.
我的第一個問題是如何從代碼中獲取該列表，但這并不是我真正需要的.
My first question is how to get that list from code but that's not what I really need.
我的最終目標是編寫函數 isValidTimezoneId() 如果時區有效則返回 TRUE，否則返回 FALSE.>
My final goal is to write function isValidTimezoneId() that returns TRUE if timezone is valid, otherwise it should return FALSE.
function isValidTimezoneId($timezoneId) {
# ...function body...
return ?; # TRUE or FALSE
}
因此，當我在函數中使用 $timezoneId(字符串)傳遞 TZ 標識符時，我需要布爾結果.
So, when I pass TZ identifier using $timezoneId (string) in function I need boolean result.
嗯，到目前為止我所擁有的......
Well, what I have so far...
我得到的第一個解決方案是這樣的:
First solution I've got is something like this:
function isValidTimezoneId($timezoneId) {
$savedZone = date_default_timezone_get(); # save current zone
$res = $savedZone == $timezoneId; # it's TRUE if param matches current zone
if (!$res) { # 0r...
@date_default_timezone_set($timezoneId); # try to set new timezone
$res = date_default_timezone_get() == $timezoneId; # it's true if new timezone set matches param string.
}
date_default_timezone_set($savedZone); # restore back old timezone
return $res; # set result
}
效果很好，但我想要另一種解決方案(以避免嘗試設置錯誤的時區)
That works perfectly, but I want another solution (to avoid trying to set wrong timezone)
然后，我試圖獲取有效時區標識符的列表，并使用 in_array() 對照參數檢查它 函數.所以我嘗試使用 timezone_identifiers_list()，但事實并非如此很好，因為此函數返回的數組中缺少很多時區(DateTimeZone::listIdentifiers()).乍一看，這正是我要找的.
Then, I was trying to get list of valid timezone identifiers and check it against parameter using in_array() function. So I've tried to use timezone_identifiers_list(), but that was not so good because a lot of timezones was missing in array returned by this function (alias of DateTimeZone::listIdentifiers()). At first sight that was exactly what I was looking for.
function isValidTimezoneId($timezoneId) {
$zoneList = timezone_identifiers_list(); # list of (all) valid timezones
return in_array($timezoneId, $zoneList); # set result
}
這段代碼看起來不錯而且簡單，但我發現 $zoneList 數組包含約 400 個元素.根據我的計算，它應該返回 550+ 個元素.缺少 150 多個元素......所以這還不足以解決我的問題.
This code looks nice and easy but than I've found that $zoneList array contains ~400 elements. According to my calculations it should return 550+ elements. 150+ elements are missing... So that's not good enough as solution for my problem.
這是我試圖找到完美解決方案的最后一步.使用此方法返回的數組，我可以提取所有 PHP 支持的時區標識符.
This is last step on my way trying to find perfect solution. Using array returned by this method I can extract all timezone identifiers supported by PHP.
function createTZlist() {
$tza = DateTimeZone::listAbbreviations();
$tzlist = array();
foreach ($tza as $zone)
foreach ($zone as $item)
if (is_string($item['timezone_id']) && $item['timezone_id'] != '')
$tzlist[] = $item['timezone_id'];
$tzlist = array_unique($tzlist);
asort($tzlist);
return array_values($tzlist);
}
此函數返回 563 個元素(在 Example #2 中，我有 只有 407 個).
This function returns 563 elements (in Example #2 I've got just 407).
我試圖找出這兩個數組之間的差異:
I've tried to find differences between those two arrays:
$a1 = timezone_identifiers_list();
$a2 = createTZlist();
print_r(array_values(array_diff($a2, $a1)));
結果是:
Array
(
[0] => Africa/Asmera
[1] => Africa/Timbuktu
[2] => America/Argentina/ComodRivadavia
[3] => America/Atka
[4] => America/Buenos_Aires
[5] => America/Catamarca
[6] => America/Coral_Harbour
[7] => America/Cordoba
[8] => America/Ensenada
[9] => America/Fort_Wayne
[10] => America/Indianapolis
[11] => America/Jujuy
[12] => America/Knox_IN
[13] => America/Louisville
[14] => America/Mendoza
[15] => America/Porto_Acre
[16] => America/Rosario
[17] => America/Virgin
[18] => Asia/Ashkhabad
[19] => Asia/Calcutta
[20] => Asia/Chungking
[21] => Asia/Dacca
[22] => Asia/Istanbul
[23] => Asia/Katmandu
[24] => Asia/Macao
[25] => Asia/Saigon
[26] => Asia/Tel_Aviv
[27] => Asia/Thimbu
[28] => Asia/Ujung_Pandang
[29] => Asia/Ulan_Bator
[30] => Atlantic/Faeroe
[31] => Atlantic/Jan_Mayen
[32] => Australia/ACT
[33] => Australia/Canberra
[34] => Australia/LHI
[35] => Australia/NSW
[36] => Australia/North
[37] => Australia/Queensland
[38] => Australia/South
[39] => Australia/Tasmania
[40] => Australia/Victoria
[41] => Australia/West
[42] => Australia/Yancowinna
[43] => Brazil/Acre
[44] => Brazil/DeNoronha
[45] => Brazil/East
[46] => Brazil/West
[47] => CET
[48] => CST6CDT
[49] => Canada/Atlantic
[50] => Canada/Central
[51] => Canada/East-Saskatchewan
[52] => Canada/Eastern
[53] => Canada/Mountain
[54] => Canada/Newfoundland
[55] => Canada/Pacific
[56] => Canada/Saskatchewan
[57] => Canada/Yukon
[58] => Chile/Continental
[59] => Chile/EasterIsland
[60] => Cuba
[61] => EET
[62] => EST
[63] => EST5EDT
[64] => Egypt
[65] => Eire
[66] => Etc/GMT
[67] => Etc/GMT+0
[68] => Etc/GMT+1
[69] => Etc/GMT+10
[70] => Etc/GMT+11
[71] => Etc/GMT+12
[72] => Etc/GMT+2
[73] => Etc/GMT+3
[74] => Etc/GMT+4
[75] => Etc/GMT+5
[76] => Etc/GMT+6
[77] => Etc/GMT+7
[78] => Etc/GMT+8
[79] => Etc/GMT+9
[80] => Etc/GMT-0
[81] => Etc/GMT-1
[82] => Etc/GMT-10
[83] => Etc/GMT-11
[84] => Etc/GMT-12
[85] => Etc/GMT-13
[86] => Etc/GMT-14
[87] => Etc/GMT-2
[88] => Etc/GMT-3
[89] => Etc/GMT-4
[90] => Etc/GMT-5
[91] => Etc/GMT-6
[92] => Etc/GMT-7
[93] => Etc/GMT-8
[94] => Etc/GMT-9
[95] => Etc/GMT0
[96] => Etc/Greenwich
[97] => Etc/UCT
[98] => Etc/UTC
[99] => Etc/Universal
[100] => Etc/Zulu
[101] => Europe/Belfast
[102] => Europe/Nicosia
[103] => Europe/Tiraspol
[104] => Factory
[105] => GB
[106] => GB-Eire
[107] => GMT
[108] => GMT+0
[109] => GMT-0
[110] => GMT0
[111] => Greenwich
[112] => HST
[113] => Hongkong
[114] => Iceland
[115] => Iran
[116] => Israel
[117] => Jamaica
[118] => Japan
[119] => Kwajalein
[120] => Libya
[121] => MET
[122] => MST
[123] => MST7MDT
[124] => Mexico/BajaNorte
[125] => Mexico/BajaSur
[126] => Mexico/General
[127] => NZ
[128] => NZ-CHAT
[129] => Navajo
[130] => PRC
[131] => PST8PDT
[132] => Pacific/Ponape
[133] => Pacific/Samoa
[134] => Pacific/Truk
[135] => Pacific/Yap
[136] => Poland
[137] => Portugal
[138] => ROC
[139] => ROK
[140] => Singapore
[141] => Turkey
[142] => UCT
[143] => US/Alaska
[144] => US/Aleutian
[145] => US/Arizona
[146] => US/Central
[147] => US/East-Indiana
[148] => US/Eastern
[149] => US/Hawaii
[150] => US/Indiana-Starke
[151] => US/Michigan
[152] => US/Mountain
[153] => US/Pacific
[154] => US/Pacific-New
[155] => US/Samoa
[156] => Universal
[157] => W-SU
[158] => WET
[159] => Zulu
)
此列表包含 Example #2 未能匹配的所有有效 TZ 標識符.
This list contains all valid TZ identifiers that Example #2 failed to match.
還有四個 TZ 標識符($a1 的一部分):
There's four TZ identifiers more (part of $a1):
print_r(array_values(array_diff($a1, $a2)));
輸出
Array
(
[0] => America/Bahia_Banderas
[1] => Antarctica/Macquarie
[2] => Pacific/Chuuk
[3] => Pacific/Pohnpei
)
現在，我有了近乎完美的解決方案......
So now, I have almost perfect solution...
function isValidTimezoneId($timezoneId) {
$zoneList = createTZlist(); # list of all valid timezones (last 4 are not included)
return in_array($timezoneId, $zoneList); # set result
}
這是我的解決方案，我可以使用它.當然，我使用這個函數作為類的一部分，所以我不需要在每次方法調用時生成 $zoneList.
That's my solution and I can use it. Of course, I use this function as part of class so I don't need to generate $zoneList on every methods call.
我想知道，是否有任何更簡單(更快)的解決方案來獲取所有有效時區標識符的列表作為數組(我想避免從 DateTimeZone::listAbbreviations() 中提取該列表，如果是這樣的話可能的)?或者，如果您知道如何檢查時區參數是否有效的另一種方法，請告訴我(我再說一遍，@ 運算符不能成為解決方案的一部分).
I'm wondering, is there any easier (quicker) solution to get list of all valid timezone identifiers as array (I want to avoid extracting that list from DateTimeZone::listAbbreviations() if that's possible)? Or if you know another way how to check is timezone parameter valid, please let me know (I repeat, @ operator can't be part of solution).
<小時>附言如果您需要更多詳細信息和示例，請告訴我.我猜你沒有.
P.S. If you need more details and examples, let me know. I guess you don't.
我使用的是 PHP 5.3.5(認為這不重要).
I'm using PHP 5.3.5 (think that's not important).
任何在無效時區字符串上拋出異常的代碼部分(使用 @ 隱藏或使用 try..catch 塊捕獲)都不是我正在尋找的解決方案.
Any part of code that throws exception on invalid timezone string (hidden using @ or caught using try..catch block) is not solution I'm looking for.
我已經為這個問題付出了小代價！
現在我正在尋找如何在 PHP 數組中提取所有時區標識符列表的最簡單方法.
Now I'm looking for the easiest way how to extract list of all timezone identifiers in PHP array.
推薦答案
您的解決方案運行良好，因此如果您正在尋找速度，我會更仔細地查看您對數組所做的工作.我已經對幾千次試驗進行計時以獲得合理的平均時間，結果如下:
You solution works fine, so if it's speed you're looking for I would look more closely at what you're doing with your arrays. I've timed a few thousand trials to get reasonable average times, and these are the results:
createTZlist : 20,713 microseconds per run
createTZlist2 : 13,848 microseconds per run
這是更快的函數:
function createTZList2()
{
$out = array();
$tza = timezone_abbreviations_list();
foreach ($tza as $zone)
{
foreach ($zone as $item)
{
$out[$item['timezone_id']] = 1;
}
}
unset($out['']);
ksort($out);
return array_keys($out);
}
如果將 if 測試簡化為 if ($item['timezone_id'])，它會更快，而不是運行 489 次來捕獲單個情況下，之后取消設置空鍵會更快.
The if test is faster if you reduce it to just if ($item['timezone_id']), but rather than running it 489 times to catch a single case, it's quicker to unset the empty key afterwards.
設置哈希鍵允許我們跳過更昂貴的 array_unique() 調用.對鍵進行排序然后提取它們比提取它們然后對提取的列表進行排序要快一點.
Setting hash keys allows us the skip the array_unique() call which is more expensive. Sorting the keys and then extracting them is a tiny bit faster than extracting them and then sorting the extracted list.
如果您放棄排序(除非您比較列表，否則不需要排序)，它會減少到 12,339 微秒.
If you drop the sorting (which is not needed unless you're comparing the list), it gets down to 12,339 microseconds.
但實際上，您無論如何都不需要歸還密鑰.查看整體 isValidTimezoneId()，您最好這樣做:
But really, you don't need to return the keys anyway. Looking at the holistic isValidTimezoneId(), you'd be better off doing this:
function isValidTimezoneId2($tzid)
{
$valid = array();
$tza = timezone_abbreviations_list();
foreach ($tza as $zone)
{
foreach ($zone as $item)
{
$valid[$item['timezone_id']] = true;
}
}
unset($valid['']);
return !!$valid[$tzid];
}
也就是說，假設您每次執行只需要測試一次，否則您希望在第一次運行后保存 $valid.這種方法避免了必須進行排序或將鍵轉換為值，鍵查找比 in_array() 搜索更快，并且沒有額外的函數調用.將數組值設置為 true 而不是 1 也會在結果為真時刪除單個強制轉換.
That is, assuming you only need to test once per execution, otherwise you'd want to save $valid after the first run. This approach avoids having to do a sort or converting the keys to values, key lookups are faster than in_array() searches and there's no extra function call. Setting the array values to true instead of 1 also removes a single cast when the result is true.
這使它在我的測試機器上可靠地降低到 12 毫秒以下，幾乎是您示例時間的一半.一個有趣的微優化實驗！
This brings it reliably down to under 12ms on my test machine, almost half the time of your example. A fun experiment in micro-optimizations!
這篇關于如何從代碼中檢查時區標識符是否有效?的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！