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Fastest way to check if a value exists in a list
...= []
time_method_set_in = []
time_method_bisect = []
# adjust range down if runtime is to great or up if there are to many zero entries in any of the time_method lists
Nls = [x for x in range(10000, 30000, 1000)]
for N in Nls:
a = [x for x in range(0, N)]
random....
Standardize data columns in R
... - positional standardization ((x-median)/mad)
n3 - unitization ((x-mean)/range)
n3a - positional unitization ((x-median)/range)
n4 - unitization with zero minimum ((x-min)/range)
n5 - normalization in range <-1,1> ((x-mean)/max(abs(x-mean)))
n5a - positional normalization in range <-1...
Asking the user for input until they give a valid response
...t function:
def sanitised_input(prompt, type_=None, min_=None, max_=None, range_=None):
if min_ is not None and max_ is not None and max_ < min_:
raise ValueError("min_ must be less than or equal to max_.")
while True:
ui = input(prompt)
if type_ is not None:
...
How to convert a double to long without casting?
...gt;= Long.MIN_VALUE);
// we already know its whole and in the Long range
return Double.valueOf(specifiedNumber).longValue();
}
public static boolean isWhole(double specifiedNumber) {
// http://stackoverflow.com/questions/15963895/how-to-check-if-a-double-value-has-no...
Why does this iterative list-growing code give IndexError: list assignment index out of range?
... can't create an element by attempting to write to an index that is out of range. j[0] = "foo" will work if the list already has at least one element.
– Steve Mayne
Jan 28 '19 at 13:49
...
Generate random numbers using C++11 random library
... answer, it appears that uniform_real_distribution returns a number in the range [a, b), where you want [a, b]. To do that, our uniform_real_distibution should actually look like:
std::uniform_real_distribution<double> dist(1, std::nextafter(10, DBL_MAX));
...
Advantages of Binary Search Trees over Hash Tables
...rve more memory than they need to.
For instance, if a hash function has a range R(h) = 0...100, then you need to allocate an array of 100 (pointers-to) elements, even if you are just hashing 20 elements. If you were to use a binary search tree to store the same information, you would only allocate ...
Python initializing a list of lists [duplicate]
...instance.
To make a list of 3 different lists, do this:
x = [[] for i in range(3)]
This gives you 3 separate instances of [], which is what you want
[[]]*n is similar to
l = []
x = []
for i in range(n):
x.append(l)
While [[] for i in range(3)] is similar to:
x = []
for i in range(n):
...
Python loop that also accesses previous and next values
... edited Apr 27 '16 at 13:32
Trang Oul
12966 bronze badges
answered Jun 18 '09 at 10:28
Hank GayHank Gay
...
How to get all possible combinations of a list’s elements?
...oop through all lengths "L":
import itertools
stuff = [1, 2, 3]
for L in range(0, len(stuff)+1):
for subset in itertools.combinations(stuff, L):
print(subset)
Or -- if you want to get snazzy (or bend the brain of whoever reads your code after you) -- you can generate the chain of "co...