Wildcard array loop in PHP - php

Question

I have an array which contains a great deal of data, which has been generated from a JSON file. Most of the data is used to populateinput elements, but some of the keys contain hidden, default values to be used for calculations later.
The array looks something like this:
[name] => 'My App'
[default_E17] => 0.009
[default_H17] => 0.0236
[default_K17] => 50
[default_P17] => 0.0118
[default_E19] => 0.03
I want to loop over all default_* keys, and output them using HTML. Essentially, I want a foreach loop, but only for the keys whose format matches default_*. Does anyone know if this is possible?
Please note that the values in the array before [default_*] keys is variable length, so I cannot easily use an array_splice().

Answer 1

You use strpos($key, "default_") === 0 to show that it start with default_ and its not in the middle or end
$array = array();
$array['name'] = 'My App';
$array['default_E17'] = "0.009";
$array['default_H17'] = "0.0236";
$array['default_K17'] = "50";
$array['default_P17'] = "0.0118";
$array['default_E19'] = "0.03";
$array['E19_default_test'] = "1.03";
echo "<pre>";
* You can use foreach *
$list = array();
foreach ( $array as $key => $value ) {
if (strpos($key, "default_") === 0) {
$list[$key] = $value;
}
}
var_dump($list);
You can also use array_flip with array_filter
$array = array_flip(array_filter(array_flip($array),function($var) { return (strpos($var, "default_") === 0);}));
var_dump($array);
You can also use FilterIterator
class RemoveDefaultIterator extends FilterIterator {
public function accept() {
return (strpos($this->key(), "default_") === 0);
}
}
$list = new RemoveDefaultIterator(new ArrayIterator($array));
var_dump(iterator_to_array($list));
They would all Output
array
'default_E17' => string '0.009' (length=5)
'default_H17' => string '0.0236' (length=6)
'default_K17' => string '50' (length=2)
'default_P17' => string '0.0118' (length=6)
'default_E19' => string '0.03' (length=4)

Answer 2

foreach( $arr as $k => $v ) { //iterate the array
if( strpos($k, 'default_') !== FALSE ) //search if the key contains 'default_'
$default_values[] = $v; // if so, store the values for the 'default_' keys
}

Answer 3

Just iterate over your array
Foreach( $inputArray AS $key=>$val ) {
// check if key is the one we need
if( ... ) {
// it is - deal with it
}
}
depending of the keys you use if() can be simple substr() or regexp matching.

Answer 4

You can use a FilterIterator for this.
Its essetially the same as looping over the whole array, because that's the only way really, but it strips you from doing this in your productive loop, thus generating less noise.
Here's how:
class Default_FilterIterator extends FilterIterator
{
public function accept()
{
if (strpos($this->key(), 'default') === 0) {
return true;
}
return false;
}
}
$yourArray = array('default_stuff' => 'foo', 'otherstuff' => 'bar');
$filterdArray = new Default_FilterIterator(new ArrayIterator($yourArray));
foreach ($filteredArray as $key => $value) {
//deal only with default values here
}

Answer 5

foreach ($your_array as $key => $value) {
// check if the $key starst with 'default_'
if (substr($key, 0, 8) == "default_") {
//do your thing...
echo "<input type='text' value='" . $value . "'>";
}
}