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When should you use constexpr capability in C++11?
... pi = 3.1415f;
// Haven't you always wanted to do this?
// constexpr std::string awesome = "oh yeah!!!";
// UPDATE: sadly std::string lacks a constexpr ctor
struct A
{
static const int four = 4;
static const int five = 5;
constexpr int six = 6;
};
int main()
{
&A::four; // linker ...
Rails migrations: Undo default setting for a column
...ip DEFAULT at schema level:
def self.up
change_column :table, :column, :string, :null => false, :default => ""
change_column_default(:table, :column, nil)
end
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Can an array be top-level JSON-text?
...sequence of tokens. The set of tokens includes six structural characters, strings, numbers, and three literal names."
– antak
Mar 10 '16 at 11:34
add a comment
...
How do I add a path to PYTHONPATH in virtualenv
...you want this to work with any python version, just use a normal old-style string-format rather than the fancy f-string f"... {dir_path}"
– Guillaume S
Jan 2 '19 at 4:27
...
What is the difference between lock and Mutex?
...g system construct, and can be used for system-wide synchronization, using string data (instead of a pointer to data) as its identifier. Two mutexes that reference two strings in two completely different memory addresses, but having the same data, will actually utilize the same operating-system mut...
How to wait for several Futures?
...Future { println("f1!");throw new RuntimeException; 1 }
def func2 : Future[String] = Future { Thread.sleep(2000);println("f2!");"f2" }
def func3 : Future[Double] = Future { Thread.sleep(2000);println("f3!");42.0 }
val f : Future[(Int,String,Double)] = {
for {
f1 <- func1.concurrently
f...
Python non-greedy regexes
... is matched against '<H1>title</H1>', it will match the entire string, and not just '<H1>'. Adding '?' after the qualifier makes it perform the match in non-greedy or minimal fashion; as few characters as possible will be matched. Using .*? in the previous expression will match onl...
Set operations (union, intersection) on Swift array?
...let array1 = ["a", "b", "c"]
let array2 = ["a", "b", "d"]
let set1:Set<String> = Set(array1)
let set2:Set<String> = Set(array2)
Swift 3.0+ can do operations on sets as:
firstSet.union(secondSet)// Union of two sets
firstSet.intersection(secondSet)// Intersection of two sets
firstSet....
Maven2: Best practice for Enterprise Project (EAR file)
... prompted me to make a selection by entering a number or entering a search string e.g.:
513: remote -> org.xwiki.commons:xwiki-commons-component-archetype
514: remote -> org.xwiki.rendering:xwiki-rendering-archetype-macro
515: remote -> org.zkoss:zk-archetype-component
516: remote -> or...
convert from Color to brush
...ew BrushConverter().ConvertFrom(ToHexColor(color)));
public static string ToHexColor(SDColor c) => "#" + c.R.ToString("X2") + c.G.ToString("X2") + c.B.ToString("X2");
public static string ToRGBColor(SDColor c) => "RGB(" + c.R.ToString() + "," + c.G.ToString() + "," + c.B.ToStri...