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When is “i += x” different from “i = i + x” in Python?
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This depends entirely on the object i.
+= calls the __iadd__ method (if it exists -- falling back on __add__ if it doesn't exist) whereas + calls the __add__ method1 or the __radd__ method in a few cases2.
From an API perspective, __iadd__ is supposed to be used fo...
Multiple linear regression in Python
...as some other model evaluation criteria. If you want the stuff like in Akavall's answer, statsmodels has some more R-like diagnostics.
– djs
Mar 17 '16 at 18:56
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LINQ Select Distinct with Anonymous Types
...on of objects. The exact type isn't important. From it I want to extract all the unique pairs of a pair of particular properties, thusly:
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How to “perfectly” override a dict?
...or other builtins) directly. It often makes no sense, because what you actually want to do is implement the interface of a dict. And that is exactly what ABCs are for.
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How to use timeit module
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The way timeit works is to run setup code once and then make repeated calls to a series of statements. So, if you want to test sorting, some care is required so that one pass at an in-place sort doesn't affect the next pass with already sorted data (that, of course, would make the Timsort reall...
How do I detect unsigned integer multiply overflow?
I was writing a program in C++ to find all solutions of a b = c , where a , b and c together use all the digits 0-9 exactly once. The program looped over values of a and b , and it ran a digit-counting routine each time on a , b and ab to check if the digits condition was satisfied.
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What is a “callable”?
...t's clear what a metaclass is , there is an associated concept that I use all the time without knowing what it really means.
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Fastest way to list all primes below N
...4.0 |
| sundaram3 | 416.0 |
+---------------------+-------+
Of all the methods tested, allowing numpy, for n=1000000,
primesfrom2to was the fastest tested.
+---------------------+-------+
| Method | ms |
+---------------------+-------+
| primesfrom2to | 15.9 |
| p...
Filter by property
...to Python to evaluate the property--and at that point, you've already done all the work to load it.
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Is there a difference between “==” and “is”?
... a
True
In your case, the second test only works because Python caches small integer objects, which is an implementation detail. For larger integers, this does not work:
>>> 1000 is 10**3
False
>>> 1000 == 10**3
True
The same holds true for string literals:
>>> "a" i...