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From an array of objects, extract value of a property as array
...ere is a shorter way of achieving it:
let result = objArray.map(a => a.foo);
OR
let result = objArray.map(({ foo }) => foo)
You can also check Array.prototype.map().
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PowerShell: Setting an environment variable for a single command only
...ariable. But if that is what you need to do you can do it this way:
$env:FOO = 'BAR'; ./myscript
The environment variable $env:FOO can be deleted later like so:
Remove-Item Env:\FOO
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Explicitly calling a default method in Java
...s per this article you access default method in interface A using
A.super.foo();
This could be used as follows (assuming interfaces A and C both have default methods foo())
public class ChildClass implements A, C {
@Override
public void foo() {
//you could completely override ...
What are static factory methods?
... a factory method, you would simply call the class's constructor directly: Foo x = new Foo(). With this pattern, you would instead call the factory method: Foo x = Foo.create(). The constructors are marked private, so they cannot be called except from inside the class, and the factory method is m...
How to pass a single object[] to a params object[]
...imple typecast will ensure the compiler knows what you mean in this case.
Foo((object)new object[]{ (object)"1", (object)"2" }));
As an array is a subtype of object, this all works out. Bit of an odd solution though, I'll agree.
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How to make a class property? [duplicate]
... bar(cls, value):
cls._bar = value
# test instance instantiation
foo = Bar()
assert foo.bar == 1
baz = Bar()
assert baz.bar == 1
# test static variable
baz.bar = 5
assert foo.bar == 5
# test setting variable on the class
Bar.bar = 50
assert baz.bar == 50
assert foo.bar == 50
The sette...
PHP: How to use array_filter() to filter array keys?
... to ARRAY_FILTER_USE_KEY to filter by key instead of value:
$my_array = ['foo' => 1, 'hello' => 'world'];
$allowed = ['foo', 'bar'];
$filtered = array_filter(
$my_array,
function ($key) use ($allowed) {
return in_array($key, $allowed);
},
ARRAY_FILTER_USE_KEY
);
Cle...
How to get the return value from a thread in python?
The function foo below returns a string 'foo' . How can I get the value 'foo' which is returned from the thread's target?
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How to randomly select an item from a list?
...
Use random.choice()
import random
foo = ['a', 'b', 'c', 'd', 'e']
print(random.choice(foo))
For cryptographically secure random choices (e.g. for generating a passphrase from a wordlist) use secrets.choice()
import secrets
foo = ['battery', 'correct', 'ho...
What is “export default” in javascript?
...n you can import that default export by omitting the curly braces:
import foo from "foo";
foo(); // hello!
Update: As of June 2015, the module system is defined in §15.2 and the export syntax in particular is defined in §15.2.3 of the ECMAScript 2015 specification.
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