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Difference between __getattr__ vs __getattribute__
...ample based on Ned Batchelder's explanation.
__getattr__ example:
class Foo(object):
def __getattr__(self, attr):
print "looking up", attr
value = 42
self.__dict__[attr] = value
return value
f = Foo()
print f.x
#output >>> looking up x 42
f.x = 3
pr...
Checking that a List is not empty in Hamcrest
...;
E.g. if you run
assertEquals(new ArrayList<>(0), Arrays.asList("foo", "bar");
you get
java.lang.AssertionError
Expected :[]
Actual :[foo, bar]
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UnboundLocalError on local variable when reassigned after first use
...
The best example that makes it clear is:
bar = 42
def foo():
print bar
if False:
bar = 0
when calling foo() , this also raises UnboundLocalError although we will never reach to line bar=0, so logically local variable should never be created.
The mystery lies i...
Checking length of dictionary object [duplicate]
...setting 0 on the object, or are you relying on custom string keys? eg obj['foo'] = 'bar';. If the latter, again, why the need for length?
Edit #1: Why can't you just do this?
list = [ {name:'john'}, {name:'bob'} ];
Then iterate over list? The length is already set.
...
Can C++ code be valid in both C++03 and C++11 but do different things?
...
}
Operator new may now throw other exceptions than std::bad_alloc
struct foo { void *operator new(size_t x){ throw std::exception(); } }
try {
foo *f = new foo();
} catch (std::bad_alloc &) {
// c++03 code
} catch (std::exception &) {
// c++11 code
}
User-declared destructors ...
Unpacking array into separate variables in JavaScript
...two = arr[1];
ES6 will allow destructuring assignment:
let [x, y] = ['foo', 'bar'];
console.log(x); // 'foo'
console.log(y); // 'bar'
Or, to stick to your initial example:
var arr = ['one', 'two'];
var [one, two] = arr;
You could also create a default value:
const [one = 'one', two = 'two...
Why does an NSInteger variable have to be cast to long when used as a format argument?
...nd all the casts and choosing the right string format specifier.
NSNumber foo = @9000;
NSLog(@"foo: %@", foo);
NSInteger bar = 9001;
NSLog(@"bar: %@", @(bar));
It also works for NSUIntegers without having to worry about that.
See answer to NSInteger and NSUInteger in a mixed 64bit / 32bit enviro...
Comparing two collections for equality irrespective of the order of items in them
...collections for equality.
/// </summary>
/// <param name="foo">The first collection.</param>
/// <param name="bar">The second collection.</param>
/// <returns>True if both collections have the same content, false otherwise.</returns>
publ...
Is it possible to dynamically compile and execute C# code fragments?
...ers = new CompilerParameters(new[] { "mscorlib.dll", "System.Core.dll" }, "foo.exe", true);
parameters.GenerateExecutable = true;
CompilerResults results = csc.CompileAssemblyFromSource(parameters,
@"using System.Linq;
class Program {
public static v...
When do you use the “this” keyword? [closed]
... 8. To invoke an extension method on the current instance (this.Foo(); will work, but Foo() will not)
– Marc Gravell♦
Nov 17 '11 at 13:20
4
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