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What does auto&& tell us?
...value or rvalue expression and I will preserve its constness. This is typically used for forwarding (usually with T&&). The reason this works is because a "universal reference", auto&& or T&&, will bind to anything.
You might say, well why not just use a const auto& beca...
How to make my custom type to work with “range-based for loops”?
...hanges, and compilers that do not.
The objects returned do not have to actually be iterators. The for(:) loop, unlike most parts of the C++ standard, is specified to expand to something equivalent to:
for( range_declaration : range_expression )
becomes:
{
auto && __range = range_expressi...
Understanding the Use of ColorMatrix and ColorMatrixColorFilter to Modify a Drawable's Hue
...working on a UI for an app, and I'm attempting to use grayscale icons, and allow the user to change the theme to a color of their choosing. To do this, I'm trying to just apply a ColorFilter of some sort to overlay a color on top of the drawable. I've tried using PorterDuff.Mode.MULTIPLY, and it wor...
Why do we copy then move?
...rvalues, the above would not compile.
Won't a copy be expensive, especially given something like std::string?
If you pass an rvalue, that will be moved into str, and that will eventually be moved into data. No copying will be performed. If you pass an lvalue, on the other hand, that lvalue wil...
How should one use std::optional?
...std::string s, int& i);
Another way that this could be done is especially bad:
int* try_parse_int(std::string s); //return nullptr if fail
This requires dynamic memory allocation, worrying about ownership, etc. - always prefer one of the other two signatures above.
Another example:
clas...
Multi-gradient shapes
...intDrawable();
p.setShape(new RectShape());
p.setShaderFactory(sf);
Basically, the int array allows you to select multiple color stops, and the following float array defines where those stops are positioned (from 0 to 1). You can then, as stated, just use this as a standard Drawable.
Edit: Here's...
Canvas width and height in HTML5
...t would be much faster to just reset the css, no?(rather than loop through all objects)...
– EnglishAdam
Sep 11 '14 at 9:28
...
What is the correct way of using C++11's range-based for?
...x << ' ';
}
the output is something like:
[... copy constructor calls for vector<X> initialization ...]
Elements:
X copy ctor.
1 X copy ctor.
3 X copy ctor.
5 X copy ctor.
7 X copy ctor.
9
As it can be read from the output, copy constructor calls are made during range-based for l...
In Java, what is the best way to determine the size of an object?
...ect. Is there an easy way to find out the size of that object programmatically? Is there a reference that defines how large primitive types and object references are for a VM ?
...
How to select rows from a DataFrame based on column values?
...have multiple values you want to include, put them in a
list (or more generally, any iterable) and use isin:
print(df.loc[df['B'].isin(['one','three'])])
yields
A B C D
0 foo one 0 0
1 bar one 1 2
3 bar three 3 6
6 foo one 6 12
7 foo three 7 14
Note,...