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Checking if an instance's class implements an interface?
...xtension.
See: http://php.net/manual/en/function.class-implements.php
Performance Tests
Some simple performance tests show the costs of each approach:
Given an instance of an object
Object construction outside the loop (100,000 iterations)
____________________________________________
| class_...
Are static class variables possible in Python?
...thod was invoked on, even if it's a subclass. A static method lacks this information, so it cannot call an overridden method, for example.
– Seb
Oct 2 '12 at 15:58
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What's the pythonic way to use getters and setters?
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Is the setter for x called in the initializer when instantiating _x?
– Casey
Jul 3 '19 at 15:12
7
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Python read-only property
... assumption that all users are consenting adults, and thus are responsible for using things correctly themselves. However, in the rare instance where it just does not make sense for an attribute to be settable (such as a derived value, or a value read from some static datasource), the getter-only p...
Instance attribute attribute_name defined outside __init__
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The idea behind this message is for the sake of readability. We expect to find all the attributes an instance may have by reading its __init__ method.
You may still want to split initialization into other methods though. In such case, you can simply assign...
Inverse dictionary lookup in Python
Is there any straightforward way of finding a key by knowing the value within a dictionary?
13 Answers
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How to create the most compact mapping n → isprime(n) up to a limit N?
Naturally, for bool isprime(number) there would be a data structure I could query.
I define the best algorithm , to be the algorithm that produces a data structure with lowest memory consumption for the range (1, N], where N is a constant.
Just an example of what I am looking for: I could rep...
Why prefer two's complement over sign-and-magnitude for signed numbers?
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It's done so that addition doesn't need to have any special logic for dealing with negative numbers. Check out the article on Wikipedia.
Say you have two numbers, 2 and -1. In your "intuitive" way of representing numbers, they would be 0010 and 1001, respectively (I'm sticking to 4 bits fo...
Is there a TRY CATCH command in Bash
... command1 &&
#save your output
} || { # catch
# save log for exception
}
Also bash contains some error handling mechanisms, as well
set -e
it stops your script if any simple command fails.
And also why not if...else. It is your best friend.
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How to get the parents of a Python class?
...tes (as I am typing this) but this is SO much simpler than some convoluted for loop, looking into bases one class at a time, not to mention when a class extends TWO or more parent classes. Importing and using inspect just clouds the scope unnecessarily. It honestly is a shame people don't know to ...