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Undefined reference to static class member
...he static member somewhere (after the class definition). Try this:
class Foo { /* ... */ };
const int Foo::MEMBER;
int main() { /* ... */ }
That should get rid of the undefined reference.
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Speed up the loop operation in R
...Biggest problem and root of ineffectiveness is indexing data.frame, I mean all this lines where you use temp[,].
Try to avoid this as much as possible. I took your function, change indexing and here version_A
dayloop2_A <- function(temp){
res <- numeric(nrow(temp))
for (i in 1:nrow(te...
Iterate over object keys in node.js
Since Javascript 1.7 there is an Iterator object, which allows this:
5 Answers
5
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Why does Ruby have both private and protected methods?
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protected methods can be called by any instance of the defining class or its subclasses.
private methods can be called only from within the calling object. You cannot access another instance's private methods directly.
Here is a quick practical exa...
URL matrix parameters vs. query parameters
...tp://example.com/res/categories;name=foo/objects;name=green/?page=1
It really comes down to namespacing.
Note: The 'levels' of resources here are categories and objects.
If only query parameters were used for a multi-level URL, you would end up with
http://example.com/res?categories_name=foo&...
'const int' vs. 'int const' as function parameters in C++ and C
...ation relative to the type consistent and easy to remember (it also anecdotally seems to make it easier to teach to beginners).
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Reset CSS display property to default value
... value, not the browser default. The spec itself makes this note under the all property:
For example, if an author specifies all: initial on an element it will block all inheritance and reset all properties, as if no rules appeared in the author, user, or user-agent levels of the cascade.
This can ...
Adding additional data to select options using jQuery
...ata attributes from HTML5 you can add extra data to elements in a syntactically-valid manner that is also easily accessible from jQuery.
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Checking for a null int value from a Java ResultSet
... declaration. In which case your test is completely redundant.
If you actually want to do something different if the field value is NULL, I suggest:
int iVal = 0;
ResultSet rs = magicallyAppearingStmt.executeQuery(query);
if (rs.next()) {
iVal = rs.getInt("ID_PARENT");
if (rs.wasNull()) {
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EF Code First “Invalid column name 'Discriminator'” but no inheritance
I have a table in my database called SEntries (see below the CREATE TABLE statement). It has a primary key, a couple of foreign keys and nothing special about it. I have many tables in my database similar to that one, but for some reason, this table ended up with a "Discriminator" column on the EF P...