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Mastering PHP Arrays

ericchapman profile image Eric Chapman Updated on ・2 min read

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PHP Arrays

//Array declaration
$names = ['Mike', 'Peter', 'Shawn', 'John'];

//add to array
$names[] = 'Micheal';

// Array merge
$array3 = array_merge($array1, $array2);

// Array Concat with Spread Operator
$names = ['Mike', 'Peter', 'Paul'];
$people = ['John', ...$names]; // ['John', 'Mike', 'Peter', 'Paul']

//Array to string
$text = implode(', ', $names); // 'Mike, Peter, Paul'

// String to Array
echo explode(',', $text); // ['Mike', 'Peter', 'Paul']

// Direct access
echo $names[1]; //output Peter

// Remove and preserve keys
unset($names[1]); 
// It is now => [0 => 'Mike', 2 => 'Paul']

// Or remove and change keys
array_splice($names, 1, 1);
// It is now => [0 => 'Mike', 1 => 'Paul']

//loop for each array entry
foreach($names as $name) { 
   echo 'Hello ' . $name;
}

// Number of items in a Array
echo count($names);  

//Associative array:
$person = ['age' => 45, 'genre' => 'men'];

//Add to ass. array:
$person['name'] = 'Mike';

//loop ass. array key => value: 
foreach($names as $key => $value) { 
   echo $key . ' : ' . $value;
}

// Check if a specific key exist
echo array_key_exists('age', $person);

// Return keys
echo array_keys($person); // ['age', 'genre']

// Return values
echo array_values($person); // [45, 'men']

//Array filter (return a filtered array)
$filteredPeople = array_filter($people, function ($person) {
    return $person->active;
});

// Array map (return transform array):
$onlyNames = array_map(function($person) {
    return ['name' => $person->name];
}, $people);

# Search associative array
$items = [
        ['id' => '100', 'name' => 'product 1'],
        ['id' => '200', 'name' => 'product 2'],
        ['id' => '300', 'name' => 'product 3'],
        ['id' => '400', 'name' => 'product 4'],
    ];

# search all value in the 'name' column
$found_key = array_search('product 3', array_column($items, 'name'));
# return 2

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Discussion (5)

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goodevilgenius profile image
Dan Jones
$names = ['Mike', 'Peter', 'Paul'];

//Remove array entry:
unset($names['Peter']);
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That unset will not do what you want it to do. You need one of the following:

// To preserve keys
unset($names[1]); 
// It is now => [0 => 'Mike', 2 => 'Paul']

// or to change keys
array_splice($name, 1, 1);
// It is now => [0 => 'Mike', 1 => 'Paul']
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ericchapman profile image
Eric Chapman Author

Did not know that one... Thanks for the tips!

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goodevilgenius profile image
Dan Jones
//Array filter (return a filtered array)
$filteredPeople = array_filter($people, function ($person) {
    return $names->active;
});
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This also won't work. I think maybe you meant:

//Array filter (return a filtered array)
$filteredPeople = array_filter($people, function ($person) {
    return $person->active;
});
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Although, I have no idea what $person is supposed to be, since it's not clear from your examples.

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ericchapman profile image
Eric Chapman Author

Oupss. Typo $names should be $person

$person is the singular noun of the plural $people

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suckup_de profile image
Lars Moelleken

Hi, here I created a wrapper around php array functions, so that you can use it in a more OOP way. github.com/voku/Arrayy