大约有 44,000 项符合查询结果（耗时：0.0473秒） [XML]
Array versus List: When to use which?
...rable is not suitable.
For example,
var str = "This is a string";
var strChars = str.ToCharArray(); // returns array
It is clear that modification of "strChars" will not mutate the original "str" object, irrespective implementation-level knowledge of "str"'s underlying type.
But suppose that
...
What is SELF JOIN and when would you use it? [duplicate]
...et information for both people in one row, you could self join like this:
select e1.EmployeeID,
e1.FirstName,
e1.LastName,
e1.SupervisorID,
e2.FirstName as SupervisorFirstName,
e2.LastName as SupervisorLastName
from Employee e1
left outer join Employee e2 on e1.SupervisorID ...
Email validation using jQuery
...l could be written in better way. None part of domain can start with other char than [a-z0-9] (case insensitive). Also, valid e-mail (and domain) has some len limit, which is also not tested.
– tomis
Jul 5 '13 at 8:42
...
Why can Java Collections not directly store Primitives types?
...s. How would you write a collection that can store either int, or float or char? Most likely you will end up with multiple collections, so you will need an intlist and a charlist etc.
Taking advantage of the object oriented nature of Java when you write a collection class it can store any object so...
How do you join on the same table, twice, in mysql?
...
you'd use another join, something along these lines:
SELECT toD.dom_url AS ToURL,
fromD.dom_url AS FromUrl,
rvw.*
FROM reviews AS rvw
LEFT JOIN domain AS toD
ON toD.Dom_ID = rvw.rev_dom_for
LEFT JOIN domain AS fromD
ON fromD.Dom_ID = rvw.rev_dom_from
ED...
How do you list the primary key of a SQL Server table?
...
SELECT Col.Column_Name from
INFORMATION_SCHEMA.TABLE_CONSTRAINTS Tab,
INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE Col
WHERE
Col.Constraint_Name = Tab.Constraint_Name
AND Col.Table_Name = Tab.Table_Name
...
Is there any difference between GROUP BY and DISTINCT
...CT and distinct by UNION cause an oracle error, but GROUP BY worked; I was selecting only 1 column from a view and not using any aggregation; I'm still baffled why it required it, but it does confirm there is some difference in the execution. As others point out, it also lets you GROUP BY columns no...
How do I append one string to another in Python?
... _Py_ForgetReference(v);
*pv = (PyObject *)
PyObject_REALLOC((char *)v, PyBytesObject_SIZE + newsize);
if (*pv == NULL) {
PyObject_Del(v);
PyErr_NoMemory();
return -1;
}
_Py_NewReference(*pv);
sv = (PyBytesObject *) *pv;
Py_SIZE(sv) = newsize;...
What is stack unwinding?
...tion with exception handling. Here's an example:
void func( int x )
{
char* pleak = new char[1024]; // might be lost => memory leak
std::string s( "hello world" ); // will be properly destructed
if ( x ) throw std::runtime_error( "boom" );
delete [] pleak; // will only get here...
Best way to encode text data for XML in Java?
...l(str) from commons-lang. I use it in App Engine application - work like a charm. Here is the Java Doc for this function:
– Oleg K
Feb 15 '11 at 19:04
...