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What exactly does an #if 0 … #endif block do?
... even get compiled.
#if is a preprocessor command, which gets evaluated before the actual compilation step. The code inside that block doesn't appear in the compiled binary.
It's often used for temporarily removing segments of code with the intention of turning them back on later.
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How do I find out which keystore was used to sign an app?
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Thank you for this. I added a tool for doing this to my github project. github.com/RichardBronosky/ota-tools/blob/master/…
– Bruno Bronosky
Aug 1 '14 at 19:43
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How to avoid 'cannot read property of undefined' errors?
...AScript 2020 or later, see optional chaining.
TypeScript has added support for optional chaining in version 3.7.
// use it like this
obj?.a?.lot?.of?.properties
Solution for JavaScript before ECMASCript 2020 or TypeScript older than version 3.7:
A quick workaround is using a try/catch helper ...
Alphabet range in Python
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I wonder if there's a way to do the same for a specific locale, i.e. get the spanish, turkish, etc. alphabets
– Gonzalo
May 6 '16 at 23:39
ad...
How to delete duplicate lines in a file without sorting it in Unix?
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An important caveat here: if you need to do this for multiple files, and you tack more files on the end of the command, or use a wildcard… the 'seen' array will fill up with duplicate lines from ALL the files. If you instead want to treat each file independently, you'll n...
Setting the selected value on a Django forms.ChoiceField
Here is the field declaration in a form:
8 Answers
8
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How can you dynamically create variables via a while loop? [duplicate]
...ctionaries too. I wonder why I have been downvoted by some downvote sniper for my answer creating an item in globals() while the answer of Gintautas Miliauskas is upvoted and this answer that doesn't give the how-to for <dynamically create key> is upvoted 3 times.
– eyqu...
phpcms v9内容页/下载页更新时间（updatetime）为空的解决方法 - 更多技术 ...
.../content/content.php
public function add() {
if(isset($_POST['dosubmit']) || isset($_POST['dosubmit_continue'])) {
define('INDEX_HTML',true);
$catid = $_POST['info']['catid'] = intval($_POST['info']['catid']);
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js/php判断终端类型：PC访问、手机访问、微信访问 - 更多技术 - 清泛网 - ...
...里提供php的判断方法：
// 判断是否是手机端
function is_mobile() {
// 如果有HTTP_X_WAP_PROFILE则一定是移动设备
if (isset($_SERVER['HTTP_X_WAP_PROFILE'])) {
return true;
}
// 如果via信息含有wap则一定是移动设备,部分服务商...
When do items in HTML5 local storage expire?
For how long is data stored in localStorage (as part of DOM Storage in HTML5) available? Can I set an expiration time for the data which I put into local storage?
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