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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...
How to install both Python 2.x and Python 3.x in Windows
...I need to use the Python Imaging Library (PIL), ImageMagick, and wxPython, all of which require Python 2.x.
18 Answers
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Get file size, image width and height before upload
...
when the value of i is alerted in the callback function reader.onload it shows a random increment! e.g. for 4 files the value as alerted was 0 3 2 1 . Can any one explain that?
– freerunner
Mar 2 '14 at 11:16
...
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...
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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How to template If-Else structures in data-bound views?
I constantly find myself using this idiom in KO-based HTML templates:
4 Answers
4
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Linux, Why can't I write even though I have group permissions?
I want to create a file in a directory owned by the staff group which I am a member of. Why can I not do this?
6 Answers
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Getting time elapsed in Objective-C
...er to use Apple's function CACurrentMediaTime!
I also benchmarked the mach_timebase_info call and it takes approximately 19ns on my iPhone 6, so I removed the (not threadsafe) code which was caching the output of that call.
#include <mach/mach.h>
#include <mach/mach_time.h>
uint64_t g...
How to sum array of numbers in Ruby?
... using array.map(...).inject(...) is inefficient, you will iterate through all data twice. Try array.inject(0) { |sum, product| sum += product.price }
– everett1992
Apr 4 '13 at 6:11
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