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How is “int* ptr = int()” value initialization not illegal?
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+1, the constant expression bit is important and missing from the top-2 upvoted answers.
– David Rodríguez - dribeas
Nov 9 '11 at 16:43
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Summarizing multiple columns with dplyr? [duplicate]
... a bit with the dplyr-syntax. I have a data frame with different variables and one grouping variable. Now I want to calculate the mean for each column within each group, using dplyr in R.
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Where are static methods and static variables stored in Java?
...stance related).
Update for clarification:
Note that only the variables and their technical values (primitives or references) are stored in PermGen space.
If your static variable is a reference to an object that object itself is stored in the normal sections of the heap (young/old generation or...
Getting error while sending email through Gmail SMTP - “Please log in via your web browser and then
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I know this is an older issue, but I recently had the same problem and was having issues resolving it, despite attempting the DisplayUnlockCaptcha fix. This is how I got it alive.
Head over to Account Security Settings (https://www.google.com/settings/security/lesssecureapps) and enable "Ac...
Async/Await vs Threads
...b done. Ideally it doesn't use a thread at all, it posts a driver request and once the driver completes the data transfer it generates a completion notification callback. Networking is by far the most common usage, latencies of hundreds of milliseconds are common and an inevitable side-effect of s...
Understanding dispatch_async
...e background.
For instance, if I am downloading a file from the internet and I want to update the user on the progress of the download, I will run the download in the priority default queue and update the UI in the main queue asynchronously.
dispatch_async(dispatch_get_global_queue( DISPATCH_QUEU...
Why is React's concept of Virtual DOM said to be more performant than dirty model checking?
...talk at ( Pete Hunt: React: Rethinking best practices -- JSConf EU 2013 ) and the speaker mentioned that dirty-checking of the model can be slow. But isn't calculating the diff between virtual DOMs actually even less performant since the virtual DOM, in most of the cases, should be bigger than mode...
Bash script error [: !=: unary operator expected
In my script I am trying to error check if the first and only argument is equal to -v but it is an optional argument. I use an if statement but I keep getting the unary operator expected error.
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No route matches “/users/sign_out” devise rails 3
I've installed devise on my app and applied the following in my application.html.erb file:
29 Answers
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Java 8 Streams - collect vs reduce
...t argument to the operator is the return value of the previous application and the second argument is the current stream element.
collect is an aggregation operation where a "collection" is created and each element is "added" to that collection. Collections in different parts of the stream are then...