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What is the optimal length for an email address in a database?
Here is an extracted portion of my query, reflecting the EMAIL_ADDRESS column data type and property:
8 Answers
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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, $allowed);
},
ARRAY_FILTER_USE_KEY
);
Cle...
Using jQuery to compare two arrays of Javascript objects
I have two arrays of JavaScript Objects that I'd like to compare to see if they are the same. The objects may not (and most likely will not) be in the same order in each array. Each array shouldn't have any more than 10 objects. I thought jQuery might have an elegant solution to this problem, but I ...
How to get the return value from a thread in python?
The function foo below returns a string 'foo' . How can I get the value 'foo' which is returned from the thread's target?
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How to randomly select an item from a list?
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Use random.choice()
import random
foo = ['a', 'b', 'c', 'd', 'e']
print(random.choice(foo))
For cryptographically secure random choices (e.g. for generating a passphrase from a wordlist) use secrets.choice()
import secrets
foo = ['battery', 'correct', 'ho...
What is “export default” in javascript?
...n you can import that default export by omitting the curly braces:
import foo from "foo";
foo(); // hello!
Update: As of June 2015, the module system is defined in §15.2 and the export syntax in particular is defined in §15.2.3 of the ECMAScript 2015 specification.
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What is the difference between the GNU Makefile variable assignments =, ?=, := and +=?
...s evaluated when VARIABLE is accessed. It is equivalent to
ifeq ($(origin FOO), undefined)
FOO = bar
endif
See the documentation for more details.
Append
VARIABLE += value
Appending the supplied value to the existing value (or setting to that value if the variable didn't exist)
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How to properly seed random number generator
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Scala: What is a TypeTag and how do I use it?
... Scala's types are erased at runtime (type erasure). If we wanna do
class Foo
class Bar extends Foo
def meth[A](xs: List[A]) = xs match {
case _: List[String] => "list of strings"
case _: List[Foo] => "list of foos"
}
we will get warnings:
<console>:23: warning: non-variable typ...
Create instance of generic type in Java?
...type information is available via reflection. e.g.,
public abstract class Foo<E> {
public E instance;
public Foo() throws Exception {
instance = ((Class)((ParameterizedType)this.getClass().
getGenericSuperclass()).getActualTypeArguments()[0]).newInstance();
...
}
}
...