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mongodb group values by multiple fields
... $slice just off the basic aggregation result. For "large" results, run parallel queries instead for each grouping ( a demonstration listing is at the end of the answer ), or wait for SERVER-9377 to resolve, which would allow a "limit" to the number of items to $push to an array.
db.books.aggregate(...
How is a CRC32 checksum calculated?
... 1 0000 0100 1100 0001 0001 1101 1011 0111
The highest term (x32) is usually not explicitly written, so it can instead be represented in hex just as
0x 04 C1 1D B7
Feel free to count the 1s and 0s, but you'll find they match up with the polynomial, where 1 is bit 0 (or the first bit) and x ...
How much faster is Redis than mongoDB?
...benchmarks that test your case and link from this post instead, then we'll all benefit from your "tested" opinion.
– Homer6
Jan 7 '13 at 18:38
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How do I install cygwin components from the command line?
... the Cygwin package similar to apt-get on Debian or yum on redhat that allows me to install components from the command line?
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Is there a Python equivalent of the C# null-coalescing operator?
In C# there's a null-coalescing operator (written as ?? ) that allows for easy (short) null checking during assignment:
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Best general SVN Ignore Pattern?
...gardless of whether it is listed in the global ignore pattern or not. Generally you do not want *.dll being tracked by SVN however you can always explicitly add any necessary ones (which I often do in the case of third-party assemblies).
– Zach Burlingame
Apr 8...
Dealing with commas in a CSV file
...any easily-available csv library - that is to say RFC 4180.
There's actually a spec for CSV format and how to handle commas:
Fields containing line breaks (CRLF), double quotes, and commas should be enclosed in double-quotes.
http://tools.ietf.org/html/rfc4180
So, to have values foo and ...
How do you validate a URL with a regular expression in Python?
...he result of parsing gives you a netloc or path you don't like, you could call that "invalid".
– S.Lott
Jun 29 '09 at 20:44
2
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How many concurrent requests does a single Flask process receive?
...tion and simply increasing the number of --workers, what you get is essentially a number of processes (managed by Gunicorn) that each behave like the app.run() development server. 4 workers == 4 concurrent requests. This is because Gunicorn uses its included sync worker type by default.
It is impo...
Calling dynamic function with dynamic number of parameters [duplicate]
I’m looking for a trick about this. I know how to call a dynamic, arbitrary function in JavaScript, passing specific parameters, something like this:
...