大约有 47,000 项符合查询结果（耗时：0.0701秒） [XML]
How to access pandas groupby dataframe by key
...t uses data-structures already available in the groupby object.
You can select different columns using the groupby slicing:
In [22]: gb[["A", "B"]].get_group("foo")
Out[22]:
A B
0 foo 1.624345
2 foo -0.528172
4 foo 0.865408
In [23]: gb["C"].get_group("foo")
Out[23]:
0 5
2 ...
Adding a new value to an existing ENUM Type
...rget enum):
INSERT INTO pg_enum (enumtypid, enumlabel, enumsortorder)
SELECT 'type_egais_units'::regtype::oid, 'NEW_ENUM_VALUE', ( SELECT MAX(enumsortorder) + 1 FROM pg_enum WHERE enumtypid = 'type_egais_units'::regtype )
...
Rails where condition using NOT NIL
..., so you really should just use the joins predicate:
Foo.joins(:bar)
Select * from Foo Inner Join Bars ...
But, for the record, if you want a "NOT NULL" condition simply use the not predicate:
Foo.includes(:bar).where.not(bars: {id: nil})
Select * from Foo Left Outer Join Bars on .. WHERE ...
How do I specify “close existing connections” in sql script
...RE @isStatAsyncOn bit
DECLARE @jobId int
DECLARE @sqlString nvarchar(500)
SELECT @dbId = database_id,
@isStatAsyncOn = is_auto_update_stats_async_on
FROM sys.databases
WHERE name = 'db_name'
IF @isStatAsyncOn = 1
BEGIN
ALTER DATABASE [db_name] SET AUTO_UPDATE_STATISTICS_ASYNC OFF
...
Why not infer template parameter from constructor?
...iable<Variable<int>> ?
The key question is, does the compiler select the type-inferred constructor here or the copy constructor?
Trying the code out, we can see that the copy constructor is selected. To expand on the example:
Variable var(num); // infering ctor
Variable var2(va...
jQuery Ajax POST example with PHP
...}
// setup some local variables
var $form = $(this);
// Let's select and cache all the fields
var $inputs = $form.find("input, select, button, textarea");
// Serialize the data in the form
var serializedData = $form.serialize();
// Let's disable the inputs for the dura...
How to unset a JavaScript variable?
...all browsers. Running in real documents, your code examples are correct. I selected your answer as correct, but I'd appreciate it if you can edit it to include explaining window.a = 1; delete window.a; and possibly the mechanism. I can do so as well if you don't mind.
– Guss
...
SQL multiple column ordering
... 1478
Thomas | Jefferson | 1826
If you execute the query below:
SELECT * FROM People ORDER BY FirstName DESC, YearOfBirth ASC
The result set will look like this:
FirstName | LastName | YearOfBirth
----------------------------------------
Thomas | More | 1478
Thomas ...
What is the difference between jQuery's mouseout() and mouseleave()?
...
Event Mouseout will trigger when mouse leaves the selected element and also when mouse leaves it's child elements also.
Event Mouseleave element will trigger when pointer will leave the selected element only.
Reference: W3School
...
targetContentOffsetForProposedContentOffset:withScrollingVelocity without subclassing UICollectionVi
...en in interface builder I changed the collection view layout to Custom and selected my flow layout subclass.
Because you're doing it this way you can't specify items sizes, etc... in IB so in MyCollectionViewFlowLayout.m I have this...
- (void)awakeFromNib
{
self.itemSize = CGSizeMake(75.0, 75...