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How can we match a^n b^n with Java regex?
... testAll($r, $tests) {
foreach ($tests as $test) {
$isMatch = preg_match($r, $test, $groups);
$groupsJoined = join('|', $groups);
print("$test $isMatch $groupsJoined\n");
}
}
$tests = array('aaa', 'aaab', 'aaaxb', 'xaaab', 'b', 'abbb');
$r1 = '/^a+(?=b+)/';
# └...
How can I check for Python version in a program that uses new language features?
...oesn't have ternary
Also, with is available in Python 2.5, just add from __future__ import with_statement.
EDIT: to get control early enough, you could split it into different .py files and check compatibility in the main file before importing (e.g. in __init__.py in a package):
# __init__.py
#...
Assignment inside lambda expression in Python
...asons. For example, we will be able to write the following:
import sys
say_hello = lambda: (
message := "Hello world",
sys.stdout.write(message + "\n")
)[-1]
say_hello()
In Python 2, it was possible to perform local assignments as a side effect of list comprehensions.
import sys
say_hell...
PHP $_SERVER['HTTP_HOST'] vs. $_SERVER['SERVER_NAME'], am I understanding the man pages correctly?
I did a lot of searching and also read the PHP $_SERVER docs . Do I have this right regarding which to use for my PHP scripts for simple link definitions used throughout my site?
...
Convert a PHP object to an associative array
...ect
$object = new StdClass;
$object->foo = 1;
$object->bar = 2;
var_dump( (array) $object );
Output:
array(2) {
'foo' => int(1)
'bar' => int(2)
}
Example: Complex Object
class Foo
{
private $foo;
protected $bar;
public $baz;
public function __construct()
...
What it the significance of the Javascript constructor property?
...y to find attr among x's attributes. If it cant find it, it will look in x.__proto__. If it's not there either, it will look in x.__proto__.__proto__ and so on as long as __proto__ is defined.
So what is __proto__and what has it got to do with prototype? Shortly put, prototype is for "types" while ...
Test if a variable is a list or tuple
...
How about: hasattr(a, "__iter__") ?
It tells if the object returned can be iterated over as a generator. By default, tuples and lists can, but not the string types.
share...
Portable way to get file size (in bytes) in shell?
...
One would guess the portable ls -ln FILE | { read _ _ _ _ size _ && echo "$size"; } needs not fork for the second step of the pipeline, as it uses just built-ins, but Bash 4.2.37 on Linux forks twice (still only one execve, though).
– Palec
...
Javascript “this” pointer within nested function
...
@Arashsoft this in this.doSomeEffects() points to std_obj. As explained in the answer above if a function doesn't have object reference then it takes this to be a window object.
– Shivam
Jun 28 '19 at 18:46
...
How to simulate target=“_blank” in JavaScript
...
<script>
window.open('http://www.example.com?ReportID=1', '_blank');
</script>
The second parameter is optional and is the name of the target window.
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