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What is the preferred/idiomatic way to insert into a map?
... which you assign a value. Obviously, this can be inefficient if the mapped_type can benefit from being directly initialized instead of default constructed and assigned. This method also makes it impossible to determine if an insertion has indeed taken place or if you have only overwritten the value...
Is there a read-only generic dictionary available in .NET?
...lt;TKey, TValue>
{
private readonly IDictionary<TKey, TValue> _dictionary;
public ReadOnlyDictionary()
{
_dictionary = new Dictionary<TKey, TValue>();
}
public ReadOnlyDictionary(IDictionary<TKey, TValue> dictionary)
{
_dictionary = dict...
Rounding up to next power of 2
...an be used to compute log2 very efficiently. See en.wikipedia.org/wiki/Find_first_set
– Simon
Oct 4 '13 at 21:57
...
Re-raise exception with a different type and message, preserving existing information
...ble to whatever code catches the new exception.
By using this feature, the __cause__ attribute is set. The built-in exception handler also knows how to report the exception's “cause” and “context” along with the traceback.
In Python 2, it appears this use case has no good answer (as describ...
How to merge lists into a list of tuples?
...
In Python 2:
>>> list_a = [1, 2, 3, 4]
>>> list_b = [5, 6, 7, 8]
>>> zip(list_a, list_b)
[(1, 5), (2, 6), (3, 7), (4, 8)]
In Python 3:
>>> list_a = [1, 2, 3, 4]
>>> list_b = [5, 6, 7, 8]
>>> list(zi...
Is it possible to import a whole directory in sass using @import?
...
I create a file named __partials__.scss in the same directory of partials
|- __partials__.scss
|- /partials
|- __header__.scss
|- __viewport__.scss
|- ....
In __partials__.scss, I wrote these:
@import "partials/header";
@import "parti...
Checking if a string can be converted to float in Python
...
Except that you forgot to name your function "will_it_float".
– unmounted
Apr 10 '09 at 1:07
3
...
std::enable_if to conditionally compile a member function
...rying to get a simple example to work to understand how to use std::enable_if . After I read this answer , I thought it shouldn't be too hard to come up with a simple example. I want to use std::enable_if to choose between two member-functions and allow only one of them to be used.
...
Algorithm to compare two images
...).
http://en.wikipedia.org/wiki/RGB_color_space
http://upvector.com/index.php?section=tutorials&subsection=tutorials/colorspace
Another example involves something called the Hough Transform. This transform essentially decomposes an image into a set of lines. You can then take some of the '...
Proper way to return JSON using node or Express
...ing to send a json file you can use streams
var usersFilePath = path.join(__dirname, 'users.min.json');
apiRouter.get('/users', function(req, res){
var readable = fs.createReadStream(usersFilePath);
readable.pipe(res);
});
...