In PHP, all variables except objects are assigned by the mechanism called copy-on-write, while objects are assigned by reference. Which means that for the arrays with scalar values simply $b = $a already will give you a copy: $a = array(); $b = $a; $b[‘foo’] = 42; var_dump($a); Will yield: array(0) { } Whereas with … Read more
You’ll have to construct the query-string. <?php $ids = array(1, 2, 3, 7, 8, 9); $inQuery = implode(‘,’, array_fill(0, count($ids), ‘?’)); $db = new PDO(…); $stmt = $db->prepare( ‘SELECT * FROM table WHERE id IN(‘ . $inQuery . ‘)’ ); // bindvalue is 1-indexed, so $k+1 foreach ($ids as $k => $id) $stmt->bindValue(($k+1), $id); $stmt->execute(); … Read more
Both array_push and the method you described will work. $cart = array(); $cart[] = 13; $cart[] = 14; // etc //Above is correct. but below one is for further understanding $cart = array(); for($i=0;$i<=5;$i++){ $cart[] = $i; } echo “<pre>”; print_r($cart); echo “</pre>”; Is the same as: <?php $cart = array(); array_push($cart, 13); array_push($cart, 14); … Read more
It suppresses error messages — see Error Control Operators in the PHP manual.
Use usort, here’s an example adapted from the manual: function cmp($a, $b) { return strcmp($a->name, $b->name); } usort($your_data, “cmp”); You can also use any callable as the second argument. Here are some examples: Using anonymous functions (from PHP 5.3) usort($your_data, function($a, $b) {return strcmp($a->name, $b->name);}); From inside a class usort($your_data, array($this, “cmp”)); // “cmp” should … Read more
It’s the double colon operator :: (see list of parser tokens).
For syntax errors, you need to enable error display in the php.ini. By default these are turned off because you don’t want a “customer” seeing the error messages. Check this page in the PHP documentation for information on the 2 directives: error_reporting and display_errors. display_errors is probably the one you want to change. If you … Read more
Depends on your priorities. If performance is your absolute driving characteristic, then by all means use the fastest one. Just make sure you have a full understanding of the differences before you make a choice Unlike serialize() you need to add extra parameter to keep UTF-8 characters untouched: json_encode($array, JSON_UNESCAPED_UNICODE) (otherwise it converts UTF-8 characters … Read more
Try var_export You may want to check out var_export — while it doesn’t provide the same output as var_dump it does provide a second $return parameter which will cause it to return its output rather than print it: $debug = var_export($my_var, true); Why? I prefer this one-liner to using ob_start and ob_get_clean(). I also find … Read more
PHP 8 or newer: Use the str_starts_with function: str_starts_with(‘http://www.google.com’, ‘http’) PHP 7 or older: Use the substr function to return a part of a string. substr( $string_n, 0, 4 ) === “http” If you’re trying to make sure it’s not another protocol. I’d use http:// instead, since https would also match, and other things such … Read more