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Should all Python classes extend object?
...inheritance are different in ways that I won't even try to summarize here. All good documentation that I've seen about MI describes new-style classes.
Finally, old-style classes have disappeared in Python 3, and inheritance from object has become implicit. So, always prefer new style classes unless...
Two way/reverse map [duplicate]
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1
>>> del d['foo']
>>> d['bar']
Traceback (most recent call last):
File "<stdin>", line 7, in <module>
KeyError: 'bar'
I'm sure I didn't cover all the cases, but that should get you started.
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TypeError: 'NoneType' object is not iterable in Python
... Correct, But the common scenario author intended here is totally to skip the for loop instead of raising an exception. Python's design is flawed here. When None is treated as an iterable it must return empty list at least. This exception never helped anyone in real life other than m...
What is the purpose of “return await” in C#?
...n async method behave differently: when combined with using (or, more generally, any return await in a try block).
Consider these two versions of a method:
Task<SomeResult> DoSomethingAsync()
{
using (var foo = new Foo())
{
return foo.DoAnotherThingAsync();
}
}
async Tas...
Convert a PHP object to an associative array
...e Typecasting with (array) and (object) works reliably and the same across all versions since PHP 4.3. See 3v4l.org/X6lhm. If you get a syntax error, you did something wrong.
– Gordon
Nov 30 '15 at 10:26
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What is a higher kinded type in Scala?
...pply to value arguments to "construct" a value.
Value constructors are usually called "functions" or "methods". These "constructors" are also said to be "polymorphic" (because they can be used to construct "stuff" of varying "shape"), or "abstractions" (since they abstract over what varies between ...
Aren't Python strings immutable? Then why does a + “ ” + b work?
...the variable a to point at a new string "Dog eats treats". You didn't actually mutate the string "Dog". Strings are immutable, variables can point at whatever they want.
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Getting the name of a variable as a string
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OK, finally got it! Installed using the following pip3 install python-varname==0.1.5; imported using from varname import nameof
– enter_display_name_here
Jun 6 at 2:42
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How do you read from stdin?
I'm trying to do some of the code golf challenges, but they all require the input to be taken from stdin . How do I get that in Python?
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What's the best way to inverse sort in scala?
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Both sortWith and sortBy have a compact syntax:
case class Foo(time:Long, str:String)
val l = List(Foo(1, "hi"), Foo(2, "a"), Foo(3, "X"))
l.sortWith(_.time > _.time) // List(Foo(3,X), Foo(2,a), Foo(1,hi))
l.sortBy(- _.time) // List(Foo(3,X), Foo(2,a), Foo(1,hi))
l....