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What is the $? (dollar question mark) variable in shell scripting? [duplicate]
...al Parameters" http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_05_02 :
? Expands to the decimal exit status of the most recent pipeline (see Pipelines).
man bash "Special Parameters":
The shell treats several parameters specially. These parameters may only be refe...
Ruby: Easiest Way to Filter Hash Keys?
...with just the choices in it.
choices = params.select { |key, value| key.to_s.match(/^choice\d+/) }
or you can use delete_if and modify the existing Hash e.g.
params.delete_if { |key, value| !key.to_s.match(/choice\d+/) }
or if it is just the keys and not the values you want then you can do:
p...
Disable Browser Link - which toolbar
...olbar, but that toolbar doesn't show up in my visual studio. I've enabled all the debug toolbars but still no browser link button.
...
Regex to match only letters
...pends on what definition of "latin character" you choose. J, U, Ö, Ä can all be argued to be latin characters or not, based on your definition. But they are all used in languages that use the "latin alphabet" for writing.
– Joachim Sauer
Sep 1 '10 at 12:23
...
URL-parameters and logic in Django class-based views (TemplateView)
...re using a TemplateView which means that you would do the logic in your get_context_data override.
– Ngenator
Apr 2 '13 at 12:58
4
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UITableView - change section header color
...lor:[UIColor clearColor]];
return headerView;
}
Swift:
func tableView(_ tableView: UITableView!, viewForHeaderInSection section: Int) -> UIView!
{
let headerView = UIView(frame: CGRect(x: 0, y: 0, width: tableView.bounds.size.width, height: 30))
if (section == integerRepresentingYourSect...
How can I auto-elevate my batch file, so that it requests from UAC administrator rights if required?
...
You can have the script call itself with psexec's -h option to run elevated.
I'm not sure how you would detect if it's already running as elevated or not... maybe re-try with elevated perms only if there's an Access Denied error?
Or, you could simp...
Rails 4: before_filter vs. before_action
...ller::Base, before_action is just a new syntax for before_filter.
However all before_filters syntax are deprecated in Rails 5.0 and will be removed in Rails 5.1
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...
Creating PHP class instance with a string
...able functions & methods.
$func = 'my_function';
$func('param1'); // calls my_function('param1');
$method = 'doStuff';
$object = new MyClass();
$object->$method(); // calls the MyClass->doStuff() method.
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What happens if you static_cast invalid value to enum class?
...ue is specified(*), and no Undefined Behaviour (UB) is involved. More generally, as you cast from the underlying type to the enumeration type, no value in data[0] can lead to UB for the static_cast.
After CWG 1766 (C++17)
See CWG defect 1766.
The [expr.static.cast]p10 paragraph has been strengthene...