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What is the difference between packaged_task and async
...d_task won't start on it's own, you have to invoke it:
std::packaged_task<int()> task(sleep);
auto f = task.get_future();
task(); // invoke the function
// You have to wait until task returns. Since task calls sleep
// you will have to wait at least 1 second.
std::cout << "You can see...
Rails raw SQL example
...Record::Base.connection.execute(sql)
records_array would then be the result of your sql query in an array which you can iterate through.
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follo...
MVC3 Razor: Displaying html within code blocks
... use @: to escape:
@if(Model.foo)
{
@:Hello World
}
or the special <text> tag which is not outputted in the response:
@if(Model.foo)
{
<text>Hello World</text>
}
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Can I avoid the native fullscreen video player with HTML5 on iPhone or android?
I've built a web app that uses the HTML5 tag and JavaScript code that renders other content synchronized with the running video. It works great in desktop browsers: Firefox, Chrome, and Safari. On an iPhone or a DroidX, the native video player pops up and takes over the screen, thus obscuring the o...
XML schema or DTD for logback.xml?
...atical rules???? What a cop-out of an excuse!
– Ken Alton
Mar 7 '17 at 14:21
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What happens to a declared, uninitialized variable in C? Does it have a value?
... variables) are indeterminate. Reading them prior to assigning a value results in undefined behavior.
void foo() {
int x;
printf("%d", x); // the compiler is free to crash here
}
In practice, they tend to just have some nonsensical value in there initially - some compilers may even put in s...
PHP 5: const vs static
...alues can be changed.
class ClassName {
static $my_var = 10; /* defaults to public unless otherwise specified */
const MY_CONST = 5;
}
echo ClassName::$my_var; // returns 10
echo ClassName::MY_CONST; // returns 5
ClassName::$my_var = 20; // now equals 20
ClassName::MY_CONST = 20; // ...
data.table vs dplyr: can one do something well the other can't or does poorly?
...eration in addition to runtime.
2. Memory usage
Operations involving filter() or slice() in dplyr can be memory inefficient (on both data.frames and data.tables). See this post.
Note that Hadley's comment talks about speed (that dplyr is plentiful fast for him), whereas the major concern he...
How to loop through an associative array and get the key? [duplicate]
...:
$keys = array_keys($arr);
foreach($keys as $key) {
echo($key);
}
Alternatively, you can do this:
foreach($arr as $key => $value) {
echo($key);
}
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prevent property from being serialized in web API
...
ASP.NET Web API uses Json.Net as default formatter, so if your application just only uses JSON as data format, you can use [JsonIgnore] to ignore property for serialization:
public class Foo
{
public int Id { get; set; }
public string Name { get; set; }
...