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valueOf() vs. toString() in Javascript
...before I get to the answer:
var x = {
toString: function () { return "foo"; },
valueOf: function () { return 42; }
};
alert(x); // foo
"x=" + x; // "x=42"
x + "=x"; // "42=x"
x + "1"; // 421
x + 1; // 43
["x=", x].join(""); // "x=foo"
The toString function is not "trumped" by valueOf in ...
Connecting overloaded signals and slots in Qt 5
...tOverload and qNonConstOverload).
Usage example (from the docs):
struct Foo {
void overloadedFunction();
void overloadedFunction(int, QString);
};
// requires C++14
qOverload<>(&Foo:overloadedFunction)
qOverload<int, QString>(&Foo:overloadedFunction)
// same, with C+...
Groovy: what's the purpose of “def” in “def x = 0”?
...e bindings for the current script and groovy treats it (mostly) like a globally scoped variable:
x = 1
assert x == 1
assert this.binding.getVariable("x") == 1
Using the def keyword instead does not put the variable in the scripts bindings:
def y = 2
assert y == 2
try {
this.binding.getVari...
On duplicate key ignore? [duplicate]
...
Would suggest NOT using INSERT IGNORE as it ignores ALL errors (ie its a sloppy global ignore).
Instead, since in your example tag is the unique key, use:
INSERT INTO table_tags (tag) VALUES ('tag_a'),('tab_b'),('tag_c') ON DUPLICATE KEY UPDATE tag=tag;
on duplicate key pro...
LAST_INSERT_ID() MySQL
...t get it working first as I was using asp.net with MySQL and needed to add Allow User Variables=True to the Connection String to allow variables.
– Martin
Oct 1 '10 at 10:19
117
...
Is there something like Annotation Inheritance in java?
...do with programs that read the annotations on a class without loading them all the way. See Why is it not possible to extend annotations in Java?
However, types do inherit the annotations of their superclass if those annotations are @Inherited.
Also, unless you need those methods to interact, you...
Can I read the hash portion of the URL on my server-side application (PHP, Ruby, Python, etc.)?
...ect to that other url in your other page. Not awesome, and doesnt work for all use cases of course, but does work for bookmarks. Note that if you do this, you shouldnt allow redirects to absolute urls, only relative urls, to ensure you don't open yourself up to unsafe redirects
...
Why is it impossible to build a compiler that can determine if a C++ function will change the value
...
@mrsoltys, quantum computers are "only" exponentially faster for some problems, they can not solve undecidable problems.
– zch
Jul 1 '13 at 18:52
8
...
Func vs. Action vs. Predicate [duplicate]
...cher.BeginInvoke.
Predicate is just a special cased Func<T, bool> really, introduced before all of the Func and most of the Action delegates came along. I suspect that if we'd already had Func and Action in their various guises, Predicate wouldn't have been introduced... although it does impa...
Split string using a newline delimiter with Python
... # ['a,b,c', 'd,e,f', 'g,h,i', 'j,k,l']
str.split, by default, splits by all the whitespace characters. If the actual string has any other whitespace characters, you might want to use
print(data.split("\n")) # ['a,b,c', 'd,e,f', 'g,h,i', 'j,k,l']
Or as @Ashwini Chaudhary suggested in the comm...