大约有 40,000 项符合查询结果（耗时：0.0448秒） [XML]
What is the difference between “def” and “val” to define a function
...ion every time (new instance of Function1).
def even: Int => Boolean = _ % 2 == 0
even eq even
//Boolean = false
val even: Int => Boolean = _ % 2 == 0
even eq even
//Boolean = true
With def you can get new function on every call:
val test: () => Int = {
val r = util.Random.nextInt
...
Difference between Django's annotate and aggregate methods?
... in the queryset.
Aggregation
>>> Book.objects.aggregate(average_price=Avg('price'))
{'average_price': 34.35}
Returns a dictionary containing the average price of all books in the queryset.
Annotation
>>> q = Book.objects.annotate(num_authors=Count('authors'))
>>> q[...
How to post data in PHP using file_get_contents?
I'm using PHP's function file_get_contents() to fetch contents of a URL and then I process headers through the variable $http_response_header .
...
General guidelines to avoid memory leaks in C++ [closed]
...in the first place.
Don't write
Object* x = new Object;
or even
shared_ptr<Object> x(new Object);
when you can just write
Object x;
share
|
improve this answer
|
...
Get encoding of a file in Windows
...t\usr\bin.
Example:
C:\Users\SH\Downloads\SquareRoot>file *
_UpgradeReport_Files; directory
Debug; directory
duration.h; ASCII C++ program text, with CRLF line terminators
ipch; directory
main.cpp...
Linux: copy and create destination dir if it does not exist
...he info page (viewable at http://www.gnu.org/software/coreutils/manual/html_node/cp-invocation.html#cp-invocation or with info cp or man cp):
--parents
Form the name of each destination file by appending to the target
directory a slash and the specified name of the source file. The
...
ORA-30926: unable to get a stable set of rows in the source tables
...ates in the query specified in USING clause. This probably means that TABLE_A is a parent table and the same ROWID is returned several times.
You could quickly solve the problem by using a DISTINCT in your query (in fact, if 'Y' is a constant value you don't even need to put it in the query).
Assu...
Use didSelectRowAtIndexPath or prepareForSegue method for UITableView?
...() contains the correct value when prepareFroSegue... is called: tableView(_:didSelectrowAtIndexPath:) isn't called until later.
– Nicolas Miari
Jun 7 '16 at 2:21
add a commen...
Count Rows in Doctrine QueryBuilder
...
->getSingleScalarResult();
}
In some simple cases using EXTRA_LAZY entity relations is good
http://doctrine-orm.readthedocs.org/projects/doctrine-orm/en/latest/tutorials/extra-lazy-associations.html
share
...
how to emulate “insert ignore” and “on duplicate key update” (sql merge) with postgresql?
...use a query like this: "start transaction; create temporary table temporary_table as select * from test where false; copy temporary_table from 'data_file.csv'; lock table test; update test set data=temporary_table.data from temporary_table where test.id=temporary_table.id; insert into test select * ...