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Bash tool to get nth line from a file
...huge, you'd better exit after reading the required line. This way you save CPU time See time comparison at the end of the answer.
awk 'NR == num_line {print; exit}' file
If you want to give the line number from a bash variable you can use:
awk 'NR == n' n=$num file
awk -v n=$num 'NR == n' file ...
Explain the use of a bit vector for determining if all characters are unique
...cause operations with bits are very low level and can be executed as-is by CPU. BitVector allows writing a little bit less cryptic code instead plus it can store more flags.
For future reference: bit vector is also known as bitSet or bitArray. Here are some links to this data structure for differen...
Evaluating a mathematical expression in a string
...rbitrary commands
eval("9**9**9**9**9**9**9**9", {'__builtins__': None}) # CPU, memory
Note: even if you use set __builtins__ to None it still might be possible to break out using introspection:
eval('(1).__class__.__bases__[0].__subclasses__()', {'__builtins__': None})
Evaluate arithmetic expr...
What does it mean to hydrate an object?
... for your current operations. So there's no reason to waste bandwidth and CPU cycles loading, transferring, and setting this data when it's not going to be used.
Additionally, there are some ORM's, such as Doctrine, which do not hydrate objects when they are instantiated, but only when the data is...
How do I replace NA values with zeros in an R dataframe?
...am running these tests on fully numeric dataframes.
Hardware Used
3.9 GHz CPU with 24 GB RAM
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How to append rows to an R data frame
...t(r)
For 1E5 rows (measurements done on Intel(R) Core(TM) i7-4710HQ CPU @ 2.50GHz):
nr function time
4 data.frame 228.251
3 sqlite 133.716
2 data.table 3.059
1 rbindlist 169.998
0 placebo 0.202
It looks like the SQLite-based sulution, although r...
Why does changing 0.1f to 0 slow down performance by 10x?
... sets FTZ (flush to zero) and DAZ (denormal are zero) in the MXCSR, so the CPU never has to take a slow microcode assist for denormals.
– Peter Cordes
Jan 16 '19 at 10:23
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What are the differences between a multidimensional array and an array of arrays in C#?
...nal but my guess is that it has to do with some optimalization made on the CPU
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In which order should floats be added to get the most precise result?
...bly avoid using -ffast-math but that in many applications where you may be CPU-bound but don't care about precise numerical computations, (game programming for instance), -ffast-math is reasonable to use. Thus, I'd like to ammend my strongly worded "banned" comment.
– Chris A....
Proper practice for subclassing UIView?
...s. Personally, I avoid multi-pass layouts when possible because they burn CPU cycles and make everything a headache. Additionally, I put constraint code in the initializers themselves as I rarely invalidate them.
import UIKit
class MyView: UIView {
//------------------------------------------...