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MongoDB not equal to
...rd operator:
An examples for $ne, which stands for not equal:
use test
switched to db test
db.test.insert({author : 'me', post: ""})
db.test.insert({author : 'you', post: "how to query"})
db.test.find({'post': {$ne : ""}})
{ "_id" : ObjectId("4f68b1a7768972d396fe2268"), "author" : "you", "post" : ...
count(*) vs count(column-name) - which is more correct? [duplicate]
Does it make a difference if you do count(*) vs count(column-name) as in these two examples?
5 Answers
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ElasticSearch, Sphinx, Lucene, Solr, Xapian. Which fits for which usage? [closed]
...r than having a huge SQL query.
I saw elasticsearch recently and played with whoosh (a Python implementation of a search engine).
...
In log4j, does checking isDebugEnabled before logging improve performance?
...there to prevent potentially expensive computation of the log message when it involves invocation of the toString() methods of various objects and concatenating the results.
In the given example, the log message is a constant string, so letting the logger discard it is just as efficient as checking...
Rolling or sliding window iterator?
I need a rolling window (aka sliding window) iterable over a sequence/iterator/generator. Default Python iteration can be considered a special case, where the window length is 1. I'm currently using the following code. Does anyone have a more Pythonic, less verbose, or more efficient method for d...
Git: can't undo local changes (error: path … is unmerged)
...
You did it the wrong way around. You are meant to reset first, to unstage the file, then checkout, to revert local changes.
Try this:
$ git reset foo/bar.txt
$ git checkout foo/bar.txt
...
“Collection was mutated while being enumerated” on executeFetchRequest
... of the background thread. When Apple tells that each thread needs to have its own moc, you have to take it seriously : each moc must be instantiated in the thread that will be using it !
Moving the following lines...
// We instantiate the background moc
self.backgroundMOC = [[[NSManagedObjectCon...
How to read a large file - line by line?
I want to iterate over each line of an entire file. One way to do this is by reading the entire file, saving it to a list, then going over the line of interest. This method uses a lot of memory, so I am looking for an alternative.
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AtomicInteger lazySet vs. set
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Cited straight from "JDK-6275329: Add lazySet methods to atomic classes":
As probably the last little JSR166 follow-up for Mustang,
we added a "lazySet" method to the Atomic classes
(AtomicInteger, AtomicReference, etc...
Find out HTTP method in PHP [duplicate]
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$_SERVER['REQUEST_METHOD']
See the docs. It will contain the request method upper-cased (i.e. 'GET', 'HEAD', 'POST', 'PUT').
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