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Event system in Python
...r methods', which is a
simple implementation of the Observer pattern.
Basically, the handler methods (callables) are stored in an array and are each called when the event 'fires'.
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The disadvantage of Observer event systems is that you can only register the handlers on the actual Ev...
Querying DynamoDB by date
...
Updated Answer:
DynamoDB allows for specification of secondary indexes to aid in this sort of query. Secondary indexes can either be global, meaning that the index spans the whole table across hash keys, or local meaning that the index would exist w...
Knight's Shortest Path on Chessboard
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You have a graph here, where all available moves are connected (value=1), and unavailable moves are disconnected (value=0), the sparse matrix would be like:
(a1,b3)=1,
(a1,c2)=1,
.....
And the shortest path of two points in a graph can be found usin...
indexOf method in an object array?
... think to see the performance of this method vs. a simple for loop. Especially when you're running on a mobile platform with limited resources.
– Doug
Aug 17 '15 at 5:51
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What is the difference between 'my' and 'our' in Perl?
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On the other hand, our variables are package variables, and thus automatically:
global variables
definitely not private
not necessarily new
can be accessed outside the package (or lexical scope) with the
qualified namespace, as $package_name::variable.
Declaring a variable with our allows you...
Why use strict and warnings?
...tify how much it helps. It should suffice to say that they help unconditionally.
– ikegami
Nov 6 '11 at 19:42
1
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ASP.NET MVC 4 Custom Authorize Attribute with Permission Codes (without roles)
...000/svg\"\u003e\u003cpath d=\"M46.1709 9.17788C46.1709 8.26454 46.2665 7.94324 47.1084 7.58816C47.4091 7.46349 47.7169 7.36433 48.0099 7.26993C48.9099 6.97997 49.672 6.73443 49.672 5.93063C49.672 5.22043 48.9832 4.61182 48.1414 4.61182C47.4335 4.61182 46.7256 4.91628 46.0943 5.50789C45.7307 4.9328 4...
Transposing a NumPy array
...of a 1D array is still a 1D array! (If you're used to matlab, it fundamentally doesn't have a concept of a 1D array. Matlab's "1D" arrays are 2D.)
If you want to turn your 1D vector into a 2D array and then transpose it, just slice it with np.newaxis (or None, they're the same, newaxis is just mor...
Access denied for user 'root'@'localhost' while attempting to grant privileges. How do I grant privi
... basics. Though of course, that doesn't mean I haven't missed something totally obvious. :-)
13 Answers
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Is using a lot of static methods a bad thing?
I tend to declare as static all the methods in a class when that class doesn't require to keep track of internal states. For example, if I need to transform A into B and don't rely on some internal state C that may vary, I create a static transform. If there is an internal state C that I want to be ...