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What is mutex and semaphore in Java ? What is the main difference?
...e 10 clients simultaneously. Then each new client sets the semaphore until it reaches 10. When the Semaphore has 10 flags, then your thread won't accept new connections
Mutex are usually used for guarding stuff. Suppose your 10 clients can access multiple parts of the system. Then you can protect a...
Disabled form inputs do not appear in the request
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Elements with the disabled attribute are not submitted or you can say their values are not posted (see the second bullet point under Step 3 in the HTML 5 spec for building the form data set).
I.e.,
<input type="textbox" name="Per...
How to specify test directory for mocha?
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Edit : This option is deprecated : https://mochajs.org/#mochaopts
If you want to do it by still just running mocha on the command line, but wanted to run the tests in a folder ./server-tests instead of ./test, create a file ...
How to Add Stacktrace or debug Option when Building Android Studio Project
...t; Settings > Compiler (Gradle-based Android Project)
For MacOS user, it's here
Android Studio > Preferences > Build, Execution, Deployment > Compiler
like this (add --stacktrace or --debug)
(Note that the screenshot is from before 0.8.10, the option is no longer in the Compiler...
Getting Django admin url for an object
...o 1.0 there was an easy way to get the admin url of an object, and I had written a small filter that I'd use like this: <a href="{{ object|admin_url }}" .... > ... </a>
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Increase heap size in Java
I am working on a Windows 2003 server (64-bit) with 8 GB RAM. How can I increase the heap memory maximum? I am using the -Xmx1500m flag to increase the heap size to 1500 Mb. Can I increase the heap memory to 75% of physical memory (6 GB Heap)?
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How to find the statistical mode?
...internal storage mode of the object, not the value that occurs the most in its argument. But is there is a standard library function that implements the statistical mode for a vector (or list)?
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Omitting the second expression when using the if-else shorthand
Can I write the if else shorthand without the else ?
8 Answers
8
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Order data frame rows according to vector with specific order
...ame),]
name value
2 b TRUE
3 c FALSE
1 a TRUE
4 d FALSE
It will work as long as your target contains exactly the same elements as df$name, and neither contain duplicate values.
From ?match:
match returns a vector of the positions of (first) matches of its first argument
in its ...
IOS7 : UIScrollView offset in UINavigationController
...yAdjustsScrollViewInsets = false
I don't really understand the true benefit of this property though, (or why the default value is true)
The only documentation i found was there:
https://web.archive.org/web/20160405135605/https://developer.apple.com/library/ios/documentation/userexperience/conce...