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Rails migration for has_and_belongs_to_many join table
...he table gets really big then you may want to be able to save space by not allocating another id for each relationship.
– docwhat
Jun 5 '11 at 3:39
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Why is string concatenation faster than array join?
...y overhead.
On the other hand ['abc', 'def'].join('') would usually just allocate memory to lay out the new string flat in memory. (Maybe this should be optimized)
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Enumerable.Empty() equivalent for IQueryable
...umerable.Empty<T>().AsQueryable();
are preferred. Array.Empty will allocate a static typed array so only one empty array of T is created and that is shared amongst all Empty queryables.
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Why use ICollection and not IEnumerable or List on many-many/one-many relationships?
...oreach, the IEnumerable<T>.GetEnumerator() method will return a heap-allocated object, rendering the optimization impossible.
– supercat
May 10 '12 at 15:58
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Chrome DevTools Devices does not detect device when plugged in
...single ADB package it required https://forum.xda-developers.com/showthread.php?t=2317790)
Use command prompt to run ADB, in cmd go to the install directory of the ADB tools and type:
adb.exe (might need to start and stop ADB using adb kill-server and adb start-server)
Connect phone and browse to abo...
When is each sorting algorithm used? [closed]
...usly.
/**
* Some VMs reserve some header words in an array.
* Attempts to allocate larger arrays may result in
* OutOfMemoryError: Requested array size exceeds VM limit
*/
private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
(even though it actually will allow to MAX_VALUE-2)
see:
Do ...
Can we instantiate an abstract class?
...that here: -
Whenever a new class instance is created, memory space is allocated
for it with room for all the instance variables declared in the class
type and all the instance variables declared in each superclass of the
class type, including all the instance variables that may be hidden....
WKWebView not loading local files under iOS 8
...athComponent;
... then start it up like so:
_webServer = [[GCDWebServer alloc] init];
[_webServer addGETHandlerForBasePath:@"/" directoryPath:docRoot indexFilename:@"index.html" cacheAge:3600 allowRangeRequests:YES];
[_webServer startWithPort:port bonjourName:nil];
To stop it:
[_webServer stop...
how to implement a pop up dialog box in iOS
...you're looking for. Here's an example:
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"No network connection"
message:@"You must be connected to the internet to use this app."
delegate:nil
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How do I increase the scrollback buffer in a running screen session?
...nificant hiccup. The higher the value you set, the more virtual memory is allocated to the screen process when initiating the screen session. I set my ~/.screenrc to "defscrollback 123456789" and when I initiated a screen, my entire system froze up for a good 10 minutes before coming back to the p...