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Why are regular expressions so controversial? [closed]
... just slow, but the performance of the regex engine can be totally unpredictable when faced with arbitrary (user-supplied) inputs.
– Pacerier
Dec 1 '15 at 21:53
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Scala: What is a TypeTag and how do I use it?
...flect.ClassTag[List[Int]] =↩
ClassTag[class scala.collection.immutable.List]
As one can see above, they don't care about type erasure, therefore if one wants "full" types TypeTag should be used:
scala> typeTag[List[Int]]
res105: reflect.runtime.universe.TypeTag[List[Int]] = TypeTag[s...
C++ performance challenge: integer to std::string conversion
... first one is a fun implementation that doesn't use any precomputed lookup tables or explicit division/modulo. This one is competitive with the others with gcc and with all but Timo's on msvc (for a good reason that I explain below). The second algorithm is my actual submission for highest performan...
Best practices for reducing Garbage Collector activity in Javascript
...ultiple object allocations. This frequently happens with keys into lookup tables and dynamic DOM node IDs. For example, lookupTable['foo-' + x] and document.getElementById('foo-' + x) both involve an allocation since there is a string concatenation. Often you can attach keys to long-lived objects...
C++ unordered_map using a custom class type as the key
...called "bucket count". A bucket is a slot in the container's internal hash table, see e.g. unordered_map::bucket_count for more information.
– honk
Feb 15 at 8:23
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Difference between timestamps with/without time zone in PostgreSQL
...d '2011-07-01 06:30:30+05' is ignored but i'm able to do insert into test_table (date) values ('2018-03-24T00:00:00-05:00'::timestamptz); and it will convert it to utc correctly. where date is timestamp without timezone. I'm trying to understand what the main value of timestamp with timezone is an...
Redis strings vs Redis hashes to represent JSON: efficiency?
...d HSET commands is still O(1): the hash will be converted into a real hash table as soon as the number of elements it contains will grow too much
But you should not worry, you'll break hash-max-ziplist-entries very fast and there you go you are now actually at solution number 1.
Second option wil...
What characters are allowed in an email address?
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I've tried to implement this in postfix via pcre access table under a check_recipient_access restriction, first turning the 3 long pcres (from the linked page) into one line each and topping and tailing thus: /^[...pcre..]$/ DUNNO, then adding a final line /.*/ REJECT, but it stil...
Please explain the exec() function and its family
...o forth.
But they're not required to be used together. It's perfectly acceptable for a program to call fork() without a following exec() if, for example, the program contains both parent and child code (you need to be careful what you do, each implementation may have restrictions).
This was used qui...
Heap vs Binary Search Tree (BST)
...log(n) n
Delete worst log(n) log(n)
All average times on this table are the same as their worst times except for Insert.
*: everywhere in this answer, BST == Balanced BST, since unbalanced sucks asymptotically
**: using a trivial modification explained in this answer
***: log(n) for p...