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Why would I ever use push_back instead of emplace_back?
C++11 vectors have the new function emplace_back . Unlike push_back , which relies on compiler optimizations to avoid copies, emplace_back uses perfect forwarding to send the arguments directly to the constructor to create an object in-place. It seems to me that emplace_back does everything p...
Create a tar.xz in one command
I am trying to create a .tar.xz compressed archive in one command. What is the specific syntax for that?
5 Answers
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How to organize large R programs?
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The standard answer is to use packages -- see the Writing R Extensions manual as well as different tutorials on the web.
It gives you
a quasi-automatic way to organize your code by topic
strongly encourages you to write a help file, making you ...
How to make zsh run as a login shell on Mac OS X (in iTerm)?
...zsh’ (‘-’ is put as the first character of arg[0]) which is supposed to mean that it should start as a login shell.
6...
How to read a large file - line by line?
I want to iterate over each line of an entire file. One way to do this is by reading the entire file, saving it to a list, then going over the line of interest. This method uses a lot of memory, so I am looking for an alternative.
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Can you explain the concept of streams?
...quence of bytes. Each stream provides means for reading and writing bytes to its given backing store. But what is the point of the stream? Why isn't the backing store itself what we interact with?
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Changing .gitconfig location on Windows
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If you set HOME to c:\my_configuration_files\, then git will locate .gitconfig there. Editing environment variables is described here. You need to set the HOME variable, then re-open any cmd.exe window. Use the "set" command to verify that H...
What exactly does Perl's “bless” do?
...Class";
Now when you invoke a method on $object, Perl know which package to search for the method.
If the second argument is omitted, as in your example, the current package/class is used.
For the sake of clarity, your example might be written as follows:
sub new {
my $class = shift;
my $...
CSS background image alt attribute
This is one I have not had to tackle before. I need to use alt tags on all images in a site including those used by CSS background-image attribute.
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AngularJS performs an OPTIONS HTTP request for a cross-origin resource
I'm trying to setup AngularJS to communicate with a cross-origin resource where the asset host which delivers my template files is on a different domain and therefore the XHR request that angular performs must be cross-domain. I've added the appropriate CORS header to my server for the HTTP request ...