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Get statistics for each group (such as count, mean, etc) using pandas GroupBy?
...1.42 0.63 0.98 1.20 1.42 1.65 1.87
To get specific statistics, just select them,
df.groupby(['A', 'B'])['C'].describe()[['count', 'mean']]
count mean
A B
bar one 1.0 0.400157
three 1.0 2.240893
two 1.0 -0.977278
foo one 2.0 ...
Purpose of Unions in C and C++
... @legends2k: any decent optimizer will recognize bitwise operations that select an entire byte and generate code to read/write the byte, same as the union but well-defined (and portable). e.g. uint8_t getRed() const { return colour & 0x000000FF; } void setRed(uint8_t r) { colour = (colour &...
SQLite Concurrent Access
...
If most of those concurrent accesses are reads (e.g. SELECT), SQLite can handle them very well. But if you start writing concurrently, lock contention could become an issue. A lot would then depend on how fast your filesystem is, since the SQLite engine itself is extremely fast...
Good ways to manage a changelog using git?
...te a GNU-style ChangeLog.
As shown by gitlog-to-changelog --help, you may select the commits used to generate a ChangeLog file using either the option --since:
gitlog-to-changelog --since=2008-01-01 > ChangeLog
or by passing additional arguments after --, which will be passed to git-log (call...
Maven: The packaging for this project did not assign a file to the build artifact
...ins - install, as pointed with red arrow in below image.
Once I run the selected install under Lifecycle as illustrated above, the issue gone, and my maven install compile build successfully.
share
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Why the switch statement cannot be applied on strings?
...however this might not be so easy for strings (considering run-time locale selection and so on). I suppose that such a thing would have to require constexpr cases, or add in unspecified behaviour (never a thing that we want to do).
– M.M
Jun 11 '15 at 23:37
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git replacing LF with CRLF
...tory -> checked out file
How to fix
Default value for core.autocrlf is selected during git installation and stored in system-wide gitconfig (%ProgramFiles(x86)%\git\etc\gitconfig). Also there're (cascading in the following order):
– "global" (per-user) gitconfig located at ~/.gitconfig,...
Reset C int array to zero : the fastest way?
...
You can use memset, but only because our selection of types is restricted to integral types.
In general case in C it makes sense to implement a macro
#define ZERO_ANY(T, a, n) do{\
T *a_ = (a);\
size_t n_ = (n);\
for (; n_ > 0; --n_, ++a_)\
*a_ = ...
For i = 0, why is (i += i++) equal to 0?
... x is evaluated to produce the variable.
The value of x is saved.
The selected operator is invoked with the saved value of x as its argument.
The value returned by the operator is stored in the location given by the evaluation of x.
The saved value of x becomes the result of the operation.
...
Why should I use an IDE? [closed]
...the code, I can highlight a method and hit F1 to get help, right click and select "go to to definition" to jump straight to where it is defined. I hit one button and the application, with debugger automatically attached is launched for me. And so the list goes on. All the things that a developer doe...