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Extracting bits with a single multiplication
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A multiplication is a bunch of shift-and-add operations. The key is to allow overflow to "shift away" the bits we don't need and put the ones we want in the right place.
Multiplication by 4 (00000100) would shift everything left by 2 and get you to a00b0000 . To get the b to move up we need to...
How to calculate a time difference in C++
...turns the CPU time consumed by the program. So if the program is run in parallel the time returned by the function would be the accumulated of the time spent on all CPUs, rather than the time elapsed cplusplus.com/reference/ctime/clock
– Ameer Jewdaki
Aug 3 '1...
What does the slash mean in help() output?
...python functions.
Also see the Argument Clinic documentation:
To mark all parameters as positional-only in Argument Clinic, add a / on a line by itself after the last parameter, indented the same as the parameter lines.
and the (very recent addition to) the Python FAQ:
A slash in the argu...
How do I use installed packages in PyCharm?
...you use the os (ex. apt-get), or pip in a virtualenv, packages will be installed to a location already on the path.
In your example, GNU Radio is installed to the system Python 2's standard site-packages location, which is already in the path. Pointing PyCharm at the correct interpreter is enough;...
Inserting multiple rows in mysql
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When loading a table from a text file, use LOAD DATA INFILE. This is usually 20 times faster than using INSERT statements.
Optimizing INSERT Statements
You can find more tips on how to speed up your insert statements on the link above.
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How to customize the background/border colors of a grouped table view cell?
...later UITableViewCell now has a backgroundColor property that makes this really easy (especially in combination with the [UIColor colorWithPatternImage:] initializer). But I'll leave the 2.0 version of the answer here for anyone that needs it…
It's harder than it really should be. Here's how I ...
How to think in data stores instead of databases?
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The datastore makes no distinction between inserts and updates. When you call put() on an entity, that entity gets stored to the datastore with its unique key, and anything that has that key gets overwritten. Basically, each entity kind in the datastore acts like an enormous map or sorted list.
Que...
How do you get the logical xor of two variables in Python?
...e not comparing apples to oranges, is "if xor( isApple(x), isApple(y) )" really clearer than "if isApple(x) != isApple(y)" ? Not to me!
– AmigoNico
May 21 '12 at 18:27
109
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Which $_SERVER variables are safe?
...ttacker can also control and is therefore a source of an attack. This is called a "tainted" variable, and is unsafe.
2 An...
Python Logging (function name, file name, line number) using a single file
...line number (within the code) where I send a message to the log output. Finally, since this application comprises of many files, I want to create a single log file so that I can better understand the control flow of the application.
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