Topic: PHP Basics – Part 4 of 10: Arrays in PHP (Indexed, Associative, Multidimensional)

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1. What is an Array in PHP?

• An array is a special variable that can hold multiple values at once.

• In PHP, arrays can be indexed, associative, or multidimensional.

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2. Indexed Arrays

• Stores values with a numeric index (starting from 0).

$fruits = array("apple", "banana", "cherry");
echo $fruits[1]; // Output: banana

• Add elements:

$fruits[] = "grape"; // Adds to the end of the array

• Count elements:

echo count($fruits); // Output: 4

• Loop through indexed array:

foreach ($fruits as $fruit) {
    echo $fruit . "<br>";
}

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3. Associative Arrays

• Uses named keys instead of numeric indexes.

$person = array(
    "name" => "Ali",
    "age" => 30,
    "city" => "Istanbul"
);
echo $person["name"]; // Output: Ali

• Loop through associative array:

foreach ($person as $key => $value) {
    echo "$key: $value<br>";
}

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4. Multidimensional Arrays

• Arrays containing one or more arrays.

$students = array(
    array("Ali", 90, 85),
    array("Sara", 95, 88),
    array("Omar", 78, 82)
);

echo $students[0][0]; // Output: Ali
echo $students[1][2]; // Output: 88

• Loop through multidimensional array:

for ($i = 0; $i < count($students); $i++) {
    for ($j = 0; $j < count($students[$i]); $j++) {
        echo $students[$i][$j] . " ";
    }
    echo "<br>";
}

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5. Array Functions You Should Know

• count() – Number of elements
• array_push() – Add to end
• array_pop() – Remove last element
• array_merge() – Merge arrays
• in_array() – Check if value exists
• array_keys() – Get all keys
• sort(), rsort() – Sort indexed array
• asort(), ksort() – Sort associative array by value/key

$colors = array("red", "blue", "green");
sort($colors);
print_r($colors);

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6. Summary

• Arrays are powerful tools for storing multiple values.

• Indexed arrays use numeric keys; associative arrays use named keys.

• PHP supports nested arrays for more complex structures.

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Exercise

• Create a multidimensional array of 3 students with their names and 2 grades.

• Print the average grade of each student using a nested loop.

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#PHP #Arrays #Multidimensional #PHPTutorial #BackendDevelopment

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