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How does database indexing work? [closed]
...g on a field that isn’t sorted requires a Linear Search which requires N/2 block accesses (on average), where N is the number of blocks that the table spans. If that field is a non-key field (i.e. doesn’t contain unique entries) then the entire tablespace must be searched at N block accesses.
W...
How to tell whether a point is to the right or left side of a line
I have a set of points. I want to separate them into 2 distinct sets. To do this, I choose two points ( a and b ) and draw an imaginary line between them. Now I want to have all points that are left from this line in one set and those that are right from this line in the other set.
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String concatenation vs. string substitution in Python
...meit.Timer('so_q_sub(1000)','from __main__ import so_q_sub')
>>> t2 = timeit.Timer('so_q_cat(1000)','from __main__ import so_q_cat')
>>> t1.timeit(number=10000000)
12.166618871951641
>>> t2.timeit(number=10000000)
5.7813972166853773
>>> t1.timeit(number=1)
1.10349...
Fast check for NaN in NumPy
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162
Ray's solution is good. However, on my machine it is about 2.5x faster to use numpy.sum in place...
Running karma after installation results in 'karma' is not recognized as an internal or external com
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321
The command line interface is in a separate package.
To install this use:
npm install -...
'printf' vs. 'cout' in C++
...e when you print many arguments. If you have to write something like Error 2: File not found., assuming error number, and its description is placeholder, the code would look like this. Both examples work identically (well, sort of, std::endl actually flushes the buffer).
printf("Error %d: %s.\n", i...
What is the difference between UNION and UNION ALL?
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26 Answers
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Git: How to reuse/retain commit messages after 'git reset'?
...ter:
git commit -C HEAD@{1}
You can use the other options given by @user2718704.
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