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Math.random() versus Random.nextInt(int)
...ly distributed bits in its mantissa, so it is uniformly distributed in the range 0 to 1-(2^-53).
Random.nextInt(n) uses Random.next() less than twice on average- it uses it once, and if the value obtained is above the highest multiple of n below MAX_INT it tries again, otherwise is returns the ...
Plotting time in Python with Matplotlib
...e data
x = [datetime.datetime.now() + datetime.timedelta(hours=i) for i in range(12)]
y = [i+random.gauss(0,1) for i,_ in enumerate(x)]
# plot
plt.plot(x,y)
# beautify the x-labels
plt.gcf().autofmt_xdate()
plt.show()
Resulting image:
Here's the same as a scatter plot:
import datetime
impo...
When to use pip requirements file versus install_requires in setup.py?
...tool has a requirements.txt file that pins a particular version or version range of requests, that would seem to create a potential problem for my-web-app, which might have specified a conflicting version/version range.
– Reece
Mar 5 '14 at 21:53
...
When to use AtomicReference in Java?
...a use case for AtomicReference:
Consider this class that acts as a number range, and uses individual AtmomicInteger variables to maintain lower and upper number bounds.
public class NumberRange {
// INVARIANT: lower <= upper
private final AtomicInteger lower = new AtomicInteger(0);
...
How do I revert a Git repository to a previous commit?
...ate revert commits:
git revert a867b4af 25eee4ca 0766c053
# It also takes ranges. This will revert the last two commits:
git revert HEAD~2..HEAD
#Similarly, you can revert a range of commits using commit hashes (non inclusive of first hash):
git revert 0d1d7fc..a867b4a
# Reverting a merge commit
...
How to convert a number to string and vice versa in C++
...cted, for example because there is no numeric data or the number is out-of-range for the type, an exception is thrown (std::invalid_argument or std::out_of_range).
If conversion succeeded and idx is not 0, idx will contain the index of the first character that was not used for decoding. This could ...
How to use sed to remove the last n lines of a file
...he shell do the math, with the goal being to use the d command by giving a range (to remove the last 23 lines):
sed -i "$(($(wc -l < file)-22)),\$d" file
To remove the last 3 lines, from inside out:
$(wc -l < file)
Gives the number of lines of the file: say 2196
We want to remove the la...
Multiprocessing vs Threading Python [duplicate]
...t, niters):
'''
A useless CPU bound function.
'''
for i in range(niters):
result = (result * result * i + 2 * result * i * i + 3) % 10000000
return result
class CpuThread(threading.Thread):
def __init__(self, niters):
super().__init__()
self.niters = ...
Getting the last element of a list
... when you want an element only postpones the inevitable "list index out of range" - and that's what should happen when attempting to get an element from an empty list. For Strings astr[-1:] could be a valid approach since it returns the same type as astr[-1], but I don't think the ':' helps to deal ...
What does the slash mean in help() output?
What does the / mean in Python 3.4's help output for range before the closing parenthesis?
3 Answers
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