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What is hashCode used for? Is it unique?
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The quote from the MSDN is now out-of-date. The MSDN is now not as explicit about the hash code not being unique.
– user34660
Dec 26 '17 at 22:11
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Fastest Way to Find Distance Between Two Lat/Long Points
...s of Geometry data types in MyISAM table. As of Mysql 5.7.5, InnoDB tables now also support SPATIAL indices.
Create a SPATIAL index on these points
Use MBRContains() to find the values:
SELECT *
FROM table
WHERE MBRContains(LineFromText(CONCAT(
'('
, @lon + 10 / ( 111.1 / cos...
How do I build a graphical user interface in C++? [closed]
...ation)
Build it.
Congratulations, you've got your first GUI in C++.
Now you're ready to read a lot of documentation to create something more complicate than "Hello world" GUI application.
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Embedding ads on Android app?
...ke to embed ad on it. I am not sure where I should start? Is there a well known mobile ad company out there that is specialized in mobile advertising?
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SQLAlchemy: What's the difference between flush() and commit()?
... # been flushed yet.
s2.flush() # Now, Foo('B') is in the same state as
# Foo('A') was above.
print 3, s2.query(Foo).all()
s2.rollback() # Foo('B') has not been committed, and rolling
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How to securely save username/password (local)?
...e entered user name and password, use the Rfc2898DerivedBytes class (also known as Password Based Key Derivation Function 2 or PBKDF2). This is more secure than using encryption like Triple DES or AES because there is no practical way to go from the result of RFC2898DerivedBytes back to the passwor...
Why are mutable structs “evil”?
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Developing in C#, you usually need mutability ever now and then - especially with your Business Model, where you want streaming etc. to work smoothly with existing solutions. I wrote an article on how to work with mutable AND immutable data, solving most issues around mutabil...
Get boolean from database using Android and SQLite
...lean.parseBoolean(cursor.getString(booleanColumnIndex));`
though you are now limited to storing the strings "true" and "false" rather than 0 or 1.
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Generate 'n' unique random numbers within a range [duplicate]
I know how to generate a random number within a range in Python.
4 Answers
4
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What is a lambda (function)?
... = x−1 means a function substituting the symbols x−1 for the symbol y. Now imagine applying λ y to each term in the first equation. If a term is y then perform the substitution; otherwise do nothing. If you do this out on paper you'll see how applying that λ y will make the first equation solv...