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What is the difference between a HashMap and a TreeMap? [duplicate]
...mple of a SortedMap, which means that the order of the keys can be sorted, and when iterating over the keys, you can expect that they will be in order.
HashMap on the other hand, makes no such guarantee. Therefore, when iterating over the keys of a HashMap, you can't be sure what order they will b...
Mongodb Explain for Aggregation framework
...t, $geonear at the beginning of a pipeline) as well as subsequent $lookup and $graphLookup stages. Once data has been fetched into the aggregation pipeline for processing (e.g. passing through stages like $project, $unwind, and $group) further manipulation will be in-memory (possibly using temporar...
Paste a multi-line Java String in Eclipse [duplicate]
...ter enabling the feature you still have to first write two quotation marks and then paste the text inside those marks.
– Lycha
Jul 29 '10 at 13:18
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Difference between static class and singleton pattern?
What real (i.e. practical) difference exists between a static class and a singleton pattern?
39 Answers
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C++ static virtual members?
Is it possible in C++ to have a member function that is both static and virtual ? Apparently, there isn't a straightforward way to do it ( static virtual member(); is a compile error), but is there at least a way to achieve the same effect?
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“x not in y” or “not x in y”
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They always give the same result.
In fact, not 'ham' in 'spam and eggs' appears to be special cased to perform a single "not in" operation, rather than an "in" operation and then negating the result:
>>> import dis
>>> def notin():
'ham' not in 'spam and eggs'
&g...
How do you find the row count for all your tables in Postgres
...g number to monitor.
The third way is to note that the system ANALYZE command, which is executed by the autovacuum process regularly as of PostgreSQL 8.3 to update table statistics, also computes a row estimate. You can grab that one like this:
SELECT
nspname AS schemaname,relname,reltuples
FR...
Random number generation in C++11: how to generate, how does it work? [closed]
I recently came across new way to generate random numbers in C++11, but couldn't digest the papers that I read about it (what is that engine , maths term like distribution , "where all integers produced are equally likely ").
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PATH issue with pytest 'ImportError: No module named YadaYadaYada'
I used easy_install to install pytest on a mac and started writing tests for a project with a file structure likes so:
20 A...
Best practice: AsyncTask during orientation change
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Do NOT use android:configChanges to address this issue. This is very bad practice.
Do NOT use Activity#onRetainNonConfigurationInstance() either. This is less modular and not well-suited for Fragment-based applications.
You can read m...