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How does collections.defaultdict work?

... Usually, a Python dictionary throws a KeyError if you try to get an item with a key that is not currently in the dictionary. The defaultdict in contrast will simply create any items that you try to access (provided of course th...
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Resetting generator object in Python

I have a generator object returned by multiple yield. Preparation to call this generator is rather time-consuming operation. That is why I want to reuse the generator several times. ...
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Why should eval be avoided in Bash, and what should I use instead?

...rintln. We could, of course, just redirect the output of println on each call, but for the sake of example, we're not going to do that. We'll need to use eval, since variables can't be used to redirect output. function println { eval printf "$2\n" "${@:3}" $1 } function error { println '...
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Skip certain tables with mysqldump

...table=schema.table2 > db-data.sql The resulting two files are structurally sound but the dumped data is now ~500MB rather than 9GB, much better for me. I can now import these two files into another database for testing purposes without having to worry about manipulating 9GB of data or running o...
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Is it possible to forward-declare a function in Python?

...rwards is impossible, what about defining it in some other module? Technically you still define it first, but it's clean. You could create a recursion like the following: def foo(): bar() def bar(): foo() Python's functions are anonymous just like values are anonymous, yet they can be ...
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ARC and bridged cast

...__bridge_transfer? Otherwise it would seem that the moment CFRelease() is called the object is gone and points to nothing. Similarly, when you use __bridge_retain, does ARC reduce the op's retain count by 1? Else it seems that the object would never be properly released. – Tony...
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Collapse sequences of white space into a single character and trim string

...low, because it creates a new object for every substring and sends method calls to each of them. – Georg Schölly Jun 23 '11 at 18:55 2 ...
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How do you turn a Mongoose document into a plain object?

...ng is that JSON.parse(JSON.encode(doc)) works and returns an object with all of the correct properties. Is there a better way to do this? ...
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Bring element to front using CSS

... I don't really remember the circumstances of my question clearly, but my problem was, that I understood what z-index does, but still it did not work. What I have learned from this answer is, that with z-index you have to take into cons...
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How can I access and process nested objects, arrays or JSON?

...as any string can be used as key in objects. The key-value pairs are also called the "properties". Properties can be accessed either using dot notation const value = obj.someProperty; or bracket notation, if the property name would not be a valid JavaScript identifier name [spec], or the name is...