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What is the difference between `after_create` and `after_save` and when to use which?

... readers should note that, according to the docs, ActiveRecord's update_all does not invoke any callbacks, including after_* – user2426679 Jan 10 at 19:34 add a comment ...
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What are the most-used vim commands/keypresses?

...rouble wading through the gargantuan lists of things you can do in VIM and all of the keypresses for them. I'm tired of hearing "You can use 'I' for inserting text, or 'a' for appending text after the character, or 'A' for appending text at the end of the line, or…" I can't imagine everyone uses a...
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How to add images to README.md on GitHub?

...ectory not the repo, so if you have 'myimage.png' in the same dir as 'about_pics.md' then the markup is:![What is this](myimage.png) – Rich Mar 8 '17 at 2:06 ...
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How to cancel an $http request in AngularJS?

...efer(); $http.get('/someUrl', {timeout: canceler.promise}).success(successCallback); // later... canceler.resolve(); // Aborts the $http request if it isn't finished. share | improve this answer ...
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Usages of Null / Nothing / Unit in Scala

...wered Apr 23 '13 at 16:40 pagoda_5bpagoda_5b 6,84711 gold badge2323 silver badges3737 bronze badges ...
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Which comment style should I use in batch files?

...his is a comment, the caret is ignored^ echo This line is printed REM This_is_a_comment_the_caret_appends_the_next_line^ echo This line is part of the remark REM followed by some characters .:\/= works a bit different, it doesn't comment an ampersand, so you can use it as inline comment. echo Fi...
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Percentage Height HTML 5/CSS

...’, which is the nearest ancestor to also be positioned.) Alternatively, all modern browsers and IE>=9 support new CSS units relative to viewport height (vh) and viewport width (vw): div { height:100vh; } See here for more info. ...
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How do I set up a simple delegate to communicate between two view controllers?

... super.viewDidLoad() } @IBAction func btnSendDataPushed(_ sender: UIButton) { // Call the delegate method from SecondVC self.delegate?.sendData(data:self.data) dismiss(animated: true, completion: nil) } } ViewCo...
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Allow user to select camera or gallery for image

...e)); yourIntentsList.add(finalIntent); } List<ResolveInfo> listGall = packageManager.queryIntentActivities(gallIntent, 0); for (ResolveInfo res : listGall) { final Intent finalIntent = new Intent(gallIntent); finalIntent.setComponent(new ComponentName(res.activityInfo.packageName,...
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When should I make explicit use of the `this` pointer?

... Usually, you do not have to, this-> is implied. Sometimes, there is a name ambiguity, where it can be used to disambiguate class members and local variables. However, here is a completely different case where this-> is e...