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Ship an application with a database
...ase in the assets folder with the new database, saving the old database in internal storage under another name, copying the new database from the assets folder into internal storage, transferring all of the data from the old database (that was renamed earlier) into the new database and finally delet...
Android Fatal signal 11 (SIGSEGV) at 0x636f7d89 (code=1). How can it be tracked down?
...getting this error by saving an object to the shared preferences as a gson converted string. The gson String was no good, so retrieving and deserializing the object was not actually working correctly. This meant any subsequent accesses to the object resulted in this error. Scary :)
...
Selecting with complex criteria from pandas.DataFrame
...tup:
>>> import pandas as pd
>>> from random import randint
>>> df = pd.DataFrame({'A': [randint(1, 9) for x in range(10)],
'B': [randint(1, 9)*10 for x in range(10)],
'C': [randint(1, 9)*100 for x in range(10)]})
>>> df
A...
Difference between == and === in JavaScript [duplicate]
...are strict comparison operators:
JavaScript has both strict and
type-converting equality comparison.
For strict equality the objects being
compared must have the same type and:
Two strings are strictly equal when they have the same sequence of
characters, same length, and same
...
How to determine if binary tree is balanced?
... abs(Height(tree.left) - Height(tree.right)) <= 1)
Translating that into the programming language of your choice should be trivial.
Bonus exercise: this naive code sketch traverses the tree far too many times when computing the heights. Can you make it more efficient?
Super bonus exercise: ...
Task not serializable: java.io.NotSerializableException when calling function outside closure only o
...
RDDs extend the Serialisable interface, so this is not what's causing your task to fail. Now this doesn't mean that you can serialise an RDD with Spark and avoid NotSerializableException
Spark is a distributed computing engine and its main abstraction i...
Should I use string.isEmpty() or “”.equals(string)?
...always wondering why others use this so often, but didn't take null values into account. Great :-)
– Peter Wippermann
Dec 2 '10 at 10:51
10
...
Difference between shadowing and overriding in C#?
...
Well inheritance...
suppose you have this classes:
class A {
public int Foo(){ return 5;}
public virtual int Bar(){return 5;}
}
class B : A{
public new int Foo() { return 1;} //shadow
public override int Bar() {return 1;} //override
}
then when you call this:
A clA = new A();
...
Programmer Puzzle: Encoding a chess board state throughout a game
...ves”. The problem also says nothing about knowing the moves up to this point. That’s actually a problem as I’ll explain.
Castling
The game has proceeded as follows:
e4 e5
Nf3 Nc6
Bb5 a6
Ba4 Bc5
The board looks as follows:
White has the option of castling. Part of the requirements f...
How to implement one-to-one, one-to-many and many-to-many relationships while designing tables?
... # "link back" if you need
You must also put a unique constraint on the foreign key column (addess.student_id) to prevent multiple rows in the child table (address) from relating to the same row in the referenced table (student).
One-to-many: Use a foreign key on the many side of the ...