大约有 40,000 项符合查询结果（耗时：0.0391秒） [XML]
MySQL和MongoDB设计实例进行对比 - 大数据 & AI - 清泛网 - 专注C/C++及内核技术
...查询：
db.getCollection("mobiles").find({
"params": {
$all: [
{$elemMatch: {"name": "待机时间", "value": {$gt: 100}}},
{$elemMatch: {"name": "外观设计", "value": "直板"}}
]
}
});
注：查询中用到的$all，$elemMatch等高...
How to get these two divs side-by-side?
...
#parent_div_1, #parent_div_2, #parent_div_3 {
width: 100px;
height: 100px;
border: 1px solid red;
margin-right: 10px;
float: left;
}
.child_div_1 {
float: left;
margin-right: 5px;
}
Check working example at http://js...
ImportError: numpy.core.multiarray failed to import
... following command in my Mac terminal:
python -c "import numpy;print(numpy.__version__);print(numpy.__file__)";
This command gave me the version and location of numpy that I was using (turned out it was 1.6.2). I went to this location and manually replaced it with the numpy folder for 1.8, which re...
lenses, fclabels, data-accessor - which library for structure access and mutation is better
...f these libraries also provide a bunch of extra combinators on top, and usually some form of template haskell machinery to automatically generate lenses for the fields of simple record types.
With that in mind, we can turn to the different implementations:
Implementations
fclabels
fclabels is pe...
count(*) vs count(column-name) - which is more correct? [duplicate]
...
COUNT(*) counts all rows
COUNT(column) counts non-NULLs only
COUNT(1) is the same as COUNT(*) because 1 is a non-null expressions
Your use of COUNT(*) or COUNT(column) should be based on the desired output only.
...
How do I show a Save As dialog in WPF?
...alog dialog = new SaveFileDialog()
{
Filter = "Text Files(*.txt)|*.txt|All(*.*)|*"
};
if (dialog.ShowDialog() == true)
{
File.WriteAllText(dialog.FileName, fileText);
}
share
|
improve th...
Completion block for popViewController
...where animated {
coordinator.animateAlongsideTransition(nil) { _ in
completion()
}
} else {
completion()
}
}
func popViewController(animated: Bool, completion: () -> ()) {
popViewControllerAnimated(animated)
...
What does %w(array) mean?
....], curly braces %w{...} or even something like exclamation marks %w!...!. All of these have the same behavior (returning an array).
– ryanb
Aug 13 '09 at 21:40
146
...
“x not in y” or “not x in y”
...am' not in 'spam and eggs'
>>> dis.dis(notin)
2 0 LOAD_CONST 1 ('ham')
3 LOAD_CONST 2 ('spam and eggs')
6 COMPARE_OP 7 (not in)
9 POP_TOP
10 LOAD_CONST 0 (...
Rename multiple files based on pattern in Unix
...
Not present on all *nix systems. Not on Max OS X for one, and no package in fink to get it. Haven't looked at MacPorts.
– dmckee --- ex-moderator kitten
Jul 6 '09 at 16:07
...