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What are all the uses of an underscore in Scala?
...s taken on scala-lang.org and noticed a curious question: " Can you name all the uses of “_”? ". Can you? If yes, please do so here. Explanatory examples are appreciated.
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Why is the order in dictionaries and sets arbitrary?
...der:
>>> {'bar': None, 'foo': None}
{'foo': None, 'bar': None}
All slots except 3 and 4 are empty, looping over the table first lists slot 3, then slot 4, so 'foo' is listed before 'bar'.
bar and baz, however, have hash values that are exactly 8 apart and thus map to the exact same slot...
Solving “Who owns the Zebra” programmatically?
...ution in Python based on constraint-programming:
from constraint import AllDifferentConstraint, InSetConstraint, Problem
# variables
colors = "blue red green white yellow".split()
nationalities = "Norwegian German Dane Swede English".split()
pets = "birds dog cats horse zebra".sp...
List all the files that ever existed in a Git repository
Do you have a clean way to list all the files that ever existed in specified branch?
4 Answers
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List all the modules that are part of a python package?
Is there a straightforward way to find all the modules that are part of a python package? I've found this old discussion , which is not really conclusive, but I'd love to have a definite answer before I roll out my own solution based on os.listdir().
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Header files for x86 SIMD intrinsics
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These days you should normally just include <immintrin.h>. It includes everything.
GCC and clang will stop you from using intrinsics for instructions you haven't enabled at compile time (e.g. with -march=native or -mavx2 -mbmi2 -mpopcnt -mfma ...
__getattr__ on a module
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A while ago, Guido declared that all special method lookups on
new-style classes bypass __getattr__ and __getattribute__. Dunder methods had previously worked on modules - you could, for example, use a module as a context manager simply by defining __enter__...
What is the most efficient/elegant way to parse a flat table into a tree?
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Now that MySQL 8.0 supports recursive queries, we can say that all popular SQL databases support recursive queries in standard syntax.
WITH RECURSIVE MyTree AS (
SELECT * FROM MyTable WHERE ParentId IS NULL
UNION ALL
SELECT m.* FROM MyTABLE AS m JOIN MyTree AS t ON m.ParentI...
List all indexes on ElasticSearch server?
I would like to list all indexes present on an ElasticSearch server. I tried this:
22 Answers
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Is there a built-in function to print all the current properties and values of an object?
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You are really mixing together two different things.
Use dir(), vars() or the inspect module to get what you are interested in (I use __builtins__ as an example; you can use any object instead).
>>> l = dir(__builtins__)
>...