What is the best practice for defining a default/fallback value for an array?
description:
My function accepts 2 parameters. One of them is an array of options to choose from. If the array hasn't been passed, it has a default/fallback value as in example:
public function selectName($howMany = 1, $seed = ['john', 'bob', 'mark', 'cindy']){...
supporting questions:
a) Is storing filled array in default arguments a good idea?
b) Which would be better, a constant, array_merge, if(empty...?
Since the default values are shared with all of your objects, it is better to decalre them as static.
Reducing the visibility to protected is recommended
class YourClass {
protected static $_DEFAULT_SEED = array('john', 'bob', 'mark', 'cindy');
protected static $_DEFAULT_QUANTITY = 1;
public function selectName($howMany = NULL, $seed = NULL){
if (is_null($howMany)) {
$howMany = self::$_DEFAULT_QUANTITY;
}
if (is_null($seed)) {
$seed = self::$_DEFAULT_SEED;
}
//...
}
}
if (is_null($seed) || !is_integer($seed)) ...Better you pass an empty array as argument.
public function selectName($howMany = 1, $seed = array()){
$myarr=['john', 'bob', 'mark', 'cindy'];
if(count($seed)>0){
$myarr=$seed;
}
/* user $myarr now*/
}
i would do so. In such case you can set only that params, you want to change
function f($array = null) {
$params = array('a' => '1', 'b' => '2'); // default params
if ($array) $params = array_replace($params, $array);
foreach($params as $k => $v)
echo "$k => $v \n";
}
f(); // a => 1 b => 2
f(array('b' => "new")); // a => 1 b => new
In my opinion, storing the filled array in default arguments isn't a good idea. What if you call the function with an array that has not every key you need?
Example:
You want
(default): ['option1' => true, 'option2' => false]
You call the function with: ['option1' => true]
Now you call the function with an array, but not with enough keys. So in my opinion, array_merge() is the best solution here.
In my opinion, I pass the array values directly in the function
<?php
public function selectName($howMany = 1, $seed = false){
$seed = (!$seed) ? array('john', 'bob', 'mark', 'cindy') : $seed;
// rest of the job ...
}
Or if the array is used in several functions, I pass it in a class CONSTANT like this
CONST SEED_DEFAULT_VALUE = array('john', 'bob', 'mark', 'cindy');
public function selectName($howMany = 1, $seed = false){
$seed = (!$seed) ? self::SEED_DEFAULT_VALUE : $seed;
// rest of the job ...
}
