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What is the difference between ArrayList.clear() and ArrayList.removeAll()?
...gine that clear() is way faster then removeAll because it's not comparing, etc.
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How to check if an array field contains a unique value or another array in MongoDB?
... for the $all does it mean all elements AND in the expressed order or is it just unordered ?
– redben
Mar 26 '11 at 14:36
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How can I check if a command exists in a shell script? [duplicate]
...p, or type -P $binary_name if you only want to see binaries (not functions etc.)
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Can we make unsigned byte in Java
...28). However, there's nothing to stop you downcasting an int (or short) in order to achieve this:
int i = 200; // 0000 0000 0000 0000 0000 0000 1100 1000 (200)
byte b = (byte) 200; // 1100 1000 (-56 by Java specification, 200 by convention)
/*
* Will print a negative int -56 because upcasting byt...
How to install PyQt4 on Windows using pip?
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In the filenames cp27 means C-python version 2.7, cp35 means python 3.5, etc.
Since Qt is a more complicated system with a compiled C++ codebase underlying the python interface it provides you, it can be more complex to build than just a pure python code package, which means it can be hard to ins...
Using [UIColor colorWithRed:green:blue:alpha:] doesn't work with UITableView seperatorColor?
..., the same works for hex values. as sometimes we get the colors as hex, in order to not calculate them by hand we can use: for example for #C94557 it would be: [UIColor colorWithRed:(CGFloat)0xC9/0xFF green:(CGFloat)0x45/0xFF blue:(CGFloat)0x57/0xFF alpha:1.0];
– memical
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Pandas get topmost n records within each group
... 2
3 7 3 1
4 8 4 1
(Keep in mind that you might need to order/sort before, depending on your data)
EDIT: As mentioned by the questioner, use df.groupby('id').head(2).reset_index(drop=True) to remove the multindex and flatten the results.
>>> df.groupby('id').head(2).res...
Docker - how can I copy a file from an image to a host?
...tion on copying files from containers to hosts; I have a Dockerfile that fetches dependencies, compiles a build artifact from source, and runs an executable. I also want to copy the build artifact (in my case it's a .zip produced by sbt dist in '../target/`, but I think this question also appli...
How do I lowercase a string in C?
...meral with bit 5 clear will become the same character code with bit 5 set, etc) so really, seriously, don't use it.
– Ken S
May 22 '13 at 21:26
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How do I print to the debug output window in a Win32 app?
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If the project is a GUI project, no console will appear. In order to change the project into a console one you need to go to the project properties panel and set:
In "linker->System->SubSystem" the value "Console (/SUBSYSTEM:CONSOLE)"
In "C/C++->Preprocessor->Preprocesso...