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How do you query for “is not null” in Mongo?
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This will return all documents with a key called "IMAGE URL", but they may still have a null value.
db.mycollection.find({"IMAGE URL":{$exists:true}});
This will return all documents with both a key called "IMAGE URL" and a non-null value.
d...
Chrome Extension how to send data from content script to popup.html
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Although you are definitely in the right direction (and actually pretty close to the end), there are several (imo) bad practises in your code (e.g. injecting a whole library (jquery) for such a trivial task, declaring unnecessary permissions, making superflous calls to API methods etc...
Why can't I use a list as a dict key in python?
..., with the hash as, say, their memory location?
It can be done without really breaking any of the requirements, but it leads to unexpected behavior. Lists are generally treated as if their value was derived from their content's values, for instance when checking (in-)equality. Many would - underst...
Find the nth occurrence of substring in a string
...ad been thinking of doing the equivalent of .rfind('XXX'), but that would fall apart if 'XXX' appears later in the input anyway.
– Nikhil Chelliah
Jul 7 '10 at 4:17
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What is the JSF resource library for and how should it be used?
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Actually, all of those examples on the web wherein the common content/file type like "js", "css", "img", etc is been used as library name are misleading.
Real world examples
To start, let's look at how existing JSF implementati...
How do I use HTML as the view engine in Express?
...will work, but to serve out HTML, there is no need to use a view engine at all, unless you want to set up funky routing. Instead, just use the static middleware:
app.use(express.static(__dirname + '/public'));
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What's the difference between :: (double colon) and -> (arrow) in PHP?
... used to access static members, such usage is discouraged), while :: is usually used to access static members (though in a few special cases, it's used to access instance members).
In general, :: is used for scope resolution, and it may have either a class name, parent, self, or (in PHP 5.3) static...
Adding a Method to an Existing Object Instance
...that instance will be passed as the first argument whenever the method is called.
Callables that are attributes of a class (as opposed to an instance) are still unbound, though, so you can modify the class definition whenever you want:
>>> def fooFighters( self ):
... print "fooFighters...
Fastest way to get the first object from a queryset in django?
...eturn None if there aren't any. There are lots of ways to do this which all work. But I'm wondering which is the most performant.
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how to change any data type into a string in python
...lso, alternatively try repr:
mystring = repr(myvariable) # '4'
This is called "conversion" in python, and is quite common.
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