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In Python, how do I determine if an object is iterable?
...(o) will construct
an iterator that tries to fetch items from o by integer index, starting at index 0. The iterator will catch any IndexError (but no other errors) that is raised and then raises StopIteration itself.
In the most general sense, there's no way to check whether the iterator returned by...
Changing one character in a string
...efended (for love I suppose). Why not suggest adding a function MID(strVar,index,newChar) to Python core that direct accesses the char memory position, instead of unnecesarily byte shuffling with the whole string?
– oscar
Nov 27 '18 at 18:37
...
A numeric string as array key in PHP
...nd faced with someone passing an array that could have either "accidental" indexing: array('this', 'that') or "associative" indexing: array(123=>array('this', 'that')). Now, thanks to you, I can just typehint ;) +1
– Just Plain High
Dec 8 '13 at 9:09
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How to calculate moving average using NumPy?
...y be is faster than FFT based methods:
EDIT Corrected an off-by-one wrong indexing spotted by Bean in the code. EDIT
def moving_average(a, n=3) :
ret = np.cumsum(a, dtype=float)
ret[n:] = ret[n:] - ret[:-n]
return ret[n - 1:] / n
>>> a = np.arange(20)
>>> moving_aver...
pandas: filter rows of DataFrame with operator chaining
...y , etc), but the only way I've found to filter rows is via normal bracket indexing
14 Answers
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Counting inversions in an array
...earch. The number of inversions for this element will be one less than the index number of its position in B since every lower number that appears after the first element of A will be an inversion.
2a. accumulate the number of inversions to counter variable num_inversions.
2b. remove A[1] from ar...
What are the options for storing hierarchical data in a relational database? [closed]
...d. Use an Adjacency List to maintain the hierarchy and use Nested Sets to query the hierarchy.
The problem up until now has been that the coversion method from an Adjacecy List to Nested Sets has been frightfully slow because most people use the extreme RBAR method known as a "Push Stack" to do th...
JavaScript equivalent of PHP's in_array()
...n their utility packages. Check out jQuery's inArray and Prototype's Array.indexOf for examples.
jQuery's implementation of it is as simple as you might expect:
function inArray(needle, haystack) {
var length = haystack.length;
for(var i = 0; i < length; i++) {
if(haystack[i] =...
Entity Attribute Value Database vs. strict Relational Model Ecommerce
...
What if you had a single table with indexes for text values 1-n, then in C# (in ram) map what you want to what you need. It would still work like an EAV, but the "matches" would be domain models. Sort of like a serialization, but you could use SQL selects on ...
What are bitwise operators?
... several cases.
x << y
is the same as
x * 2y
if you need to quickly multiply by a power of two, but watch out for shifting a 1-bit into the top bit - this makes the number negative unless it's unsigned. It's also useful when dealing with different sizes of data. For example, reading...