大约有 48,000 项符合查询结果（耗时：0.0491秒） [XML]
What are all the uses of an underscore in Scala?
...s taken on scala-lang.org and noticed a curious question: " Can you name all the uses of “_”? ". Can you? If yes, please do so here. Explanatory examples are appreciated.
...
When should I use a composite index?
...olumn_A )
But it will not (at least not directly, maybe it can help partially if there are no better indices) help for queries that need
index( column_A, column_C )
Notice how column_B is missing.
In your original example, a composite index for two dimensions will mostly benefit queries that q...
When to use Spring Integration vs. Camel?
...
We choose Camel over Spring-Integration because the fluent API is really nice. We actually use it in Spring projects and use Spring to configure part of it. The programming API's are clear and there is a large set of sensible components.
We did a small scale shootout and basically at that t...
How to create an HTTPS server in Node.js?
...information came in very handy as I run a node.js tool (PDFJS) on top of a PHP app that was recently forced to run over https. The iframe was very unhappy to load my node.js app on an alternate, non-https port.
– lewsid
Oct 7 '14 at 16:12
...
PostgreSQL: Difference between text and varchar (character varying)
...
There is no difference, under the hood it's all varlena (variable length array).
Check this article from Depesz: http://www.depesz.com/index.php/2010/03/02/charx-vs-varcharx-vs-varchar-vs-text/
A couple of highlights:
To sum it all up:
char(n) – takes t...
How to create the most compact mapping n → isprime(n) up to a limit N?
Naturally, for bool isprime(number) there would be a data structure I could query.
I define the best algorithm , to be the algorithm that produces a data structure with lowest memory consumption for the range (1, N], where N is a constant.
Just an example of what I am looking for: I could rep...
Relationship between SciPy and NumPy
SciPy appears to provide most (but not all [1]) of NumPy's functions in its own namespace. In other words, if there's a function named numpy.foo , there's almost certainly a scipy.foo . Most of the time, the two appear to be exactly the same, oftentimes even pointing to the same function object.
...
How to select a single field for all documents in a MongoDB collection?
... include several fields. In the following operation, find() method returns all documents that match the query. In the result set, only the item and qty fields and, by default, the _id field return in the matching documents.
db.inventory.find( { type: 'food' }, { item: 1, qty: 1 } )
In this example ...
SecurityError: Blocked a frame with origin from accessing a cross-origin frame
...o not use it. This else branch is
// here just for clarity, you usually shouldn't need it.
return;
}
});
This method can be applied in both directions, creating a listener in the main page too, and receiving responses from the frame. The same logic can also be implemented i...
How to get the value from the GET parameters?
...alue';
Update: This works better:
var url = "http://www.example.com/index.php?myParam=384&login=admin"; // or window.location.href for current url
var captured = /myParam=([^&]+)/.exec(url)[1]; // Value is in [1] ('384' in our case)
var result = captured ? captured : 'myDefaultValue';
And ...