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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.* F...
How do you remove a Cookie in a Java Servlet
...okie to persist for the duration of the session. You want to set MaxAge to 0 instead.
From the API documentation:
A negative value means that the cookie is not stored persistently and will be deleted when the Web browser exits. A zero value causes the cookie to be deleted.
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(-2147483648> 0) returns true in C++?
... attempt using unsigned types to represent the value (for example, in C89/90 compilers were required to use unsigned long int, but not in C99 or C++). Implementations are allowed to do anything, since the behavior is undefined anyway.
As a side note, this is the reason why constants like INT_MIN ar...
Getting LaTeX into R Plots
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answered Sep 12 '09 at 1:11
Christopher DuBoisChristopher DuBois
36.7k2323 gold badges6565 silver badges9191 bronze badges
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In-memory size of a Python structure
...gt;>> import decimal
>>>
>>> d = {
... "int": 0,
... "float": 0.0,
... "dict": dict(),
... "set": set(),
... "tuple": tuple(),
... "list": list(),
... "str": "a",
... "unicode": u"a",
... "decimal": decimal.Decimal(0),
... "object": ob...
Cluster analysis in R: determine the optimal number of clusters
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1024
If your question is how can I determine how many clusters are appropriate for a kmeans analysi...
How to find the sum of an array of numbers
... how can I find the sum of its elements? (In this case, the sum would be 10 .)
43 Answers
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What is the difference between
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edited Aug 11 at 9:09
Alexandr Nil
14111 gold badge55 silver badges1010 bronze badges
answered No...
What is q=0.5 in Accept* HTTP headers?
...y factor. It specifies what language the user would prefer, on a scale of 0 to 1, as can be seen from the HTTP/1.1 Specification, §14.4:
Each language-range MAY be given an associated quality value which represents an estimate of the user's preference for the languages specified by that range. Th...