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How to set child process' environment variable in Makefile
...ever you can use make's export to force them to do so. Change:
test: NODE_ENV = test
to this:
test: export NODE_ENV = test
(assuming you have a sufficiently modern version of GNU make >= 3.77 ).
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Run a callback only if an attribute has changed in Rails
...
Rails 5.1+
class Page < ActiveRecord::Base
before_save :do_something, if: :will_save_change_to_status_id?
private
def do_something
# ...
end
end
The commit that changed ActiveRecord::Dirty is here: https://github.com/rails/rails/commit/16ae3db5a5c6a08383b974ae...
How to obtain the number of CPUs/cores in Linux from the command line?
...
The most portable solution I have found is the getconf command:
getconf _NPROCESSORS_ONLN
This works on both Linux and Mac OS X. Another benefit of this over some of the other approaches is that getconf has been around for a long time. Some of the older Linux machines I have to do development o...
How can I extract the folder path from file path in Python?
....path.split(os.path.abspath(existGDBPath))
('T:\\Data\\DBDesign', 'DBDesign_93_v141b.mdb')
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Convert nested Python dict to object?
...']
The alternative (original answer contents) is:
class Struct:
def __init__(self, **entries):
self.__dict__.update(entries)
Then, you can use:
>>> args = {'a': 1, 'b': 2}
>>> s = Struct(**args)
>>> s
<__main__.Struct instance at 0x01D6A738>
>>...
Detecting endianness programmatically in a C++ program
...e warned against by compiler. That's exactly what unions are for !
bool is_big_endian(void)
{
union {
uint32_t i;
char c[4];
} bint = {0x01020304};
return bint.c[0] == 1;
}
The principle is equivalent to the type case as suggested by others, but this is clearer - and...
What really happens in a try { return x; } finally { x = null; } statement?
...ged
{
.maxstack 1
.locals init (
[0] int32 CS$1$0000)
L_0000: call int32 Program::SomeNumber()
L_0005: stloc.0
L_0006: leave.s L_000e
L_0008: call void Program::Foo()
L_000d: endfinally
L_000e: ldloc.0
L_000f: ret
.try L_0000 to L_0008 finally hand...
Positioning MKMapView to show multiple annotations at once
...(IBAction)zoomOut:(id)sender {
CLLocationCoordinate2D southWest = _newLocation.coordinate;
CLLocationCoordinate2D northEast = southWest;
southWest.latitude = MIN(southWest.latitude, _annotation.coordinate.latitude);
southWest.longitude = MIN(southWest.longitude, _an...
How to find the width of a div using vanilla JavaScript?
... edited Nov 4 '15 at 11:07
sudo_dudo
50744 silver badges1616 bronze badges
answered Sep 12 '14 at 18:10
user3...
Can I have onScrollListener for a ScrollView?
...dited Sep 16 '16 at 6:48
Pavneet_Singh
33.3k55 gold badges3939 silver badges5757 bronze badges
answered Apr 29 '14 at 13:06
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