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How do I concatenate two lists in Python?
...umming iterables into a
list, such as my_list + list(my_tuple) + list(my_range) which is now
equivalent to just [*my_list, *my_tuple, *my_range].
So while addition with + would raise a TypeError due to type mismatch:
l = [1, 2, 3]
r = range(4, 7)
res = l + r
The following won't:
res = [*l,...
The tilde operator in Python
... with s[len(s) - 2].
As for your other question, this can be useful for a range of bitwise hacks.
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Have a reloadData for a UITableView animate when changing
... sections :) - [_tableView reloadSections:[NSIndexSet indexSetWithIndexesInRange:NSMakeRange(0, sectionCount)] withRowAnimation:UITableViewRowAnimationFade];
– lobianco
Feb 4 '14 at 0:16
...
How to generate a random number in C++?
... with implementation-defined algorithm. Function rand() produces values in range [0, RAND_MAX].
Quote from C11 standard (ISO/IEC 9899:2011):
The srand function uses the argument as a seed for a new sequence of
pseudo-random numbers to be returned by subsequent calls to rand. If
srand is then called...
Generating random integer from a range
I need a function which would generate a random integer in given range (including border values). I don't unreasonable quality/randomness requirements, I have four requirements:
...
Add single element to array in numpy
...nvert to an array afterward.
Using np.append:
b = np.array([0])
for k in range(int(10e4)):
b = np.append(b, k)
1.2 s ± 16.1 ms per loop (mean ± std. dev. of 7 runs, 1 loop each)
Using python list converting to array afterward:
d = [0]
for k in range(int(10e4)):
d.append(k)
f = np.arra...
How to extract the n-th elements from a list of tuples?
...slower than the list comprehension:
setup = 'elements = [(1,1,1) for _ in range(100000)];from operator import itemgetter'
method1 = '[x[1] for x in elements]'
method2 = 'map(itemgetter(1), elements)'
import timeit
t = timeit.Timer(method1, setup)
print('Method 1: ' + str(t.timeit(100)))
t = timeit...
Understanding generators in Python
...describe certain common types of generators:
>>> g = (n for n in range(3, 5))
>>> next(g)
3
>>> next(g)
4
>>> next(g)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
StopIteration
Note that generator expressions are much lik...
Python Empty Generator Function
...ng a hard time coming up with a use case for this for which iter([]) or (x)range(0) wouldn't work equally well.
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How to declare an array in Python?
...an list with the first 30 cells already filled.
So
f = []
for i in range(30):
f.append(0)
An example to where this could be used is in Fibonacci sequence.
See problem 2 in Project Euler
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