PHP array_column() - Complete Guide with Examples

The array_column() function extracts a single column from a multi-dimensional array. It’s extremely useful for working with database results and structured data.

This guide covers everything about array_column(), from basic usage to advanced patterns.

Introduction to array_column()

array_column() extracts values from a specified column in a multi-dimensional array, similar to SQL’s SELECT column operation.

Key Characteristics:

• Extracts column values
• Can use index key
• Works with associative arrays
• Returns indexed array

Common Use Cases:

• Extract IDs from database results
• Get specific field from array of objects
• Transform data structures
• Create lookup arrays

Syntax and Parameters

Function Signature

array_column(array $array, string|int|null $column_key, string|int|null $index_key = null): array

Parameters

$array: Multi-dimensional array $column_key: Column to extract $index_key: Optional key for result array

Basic Usage Examples

Extract Column

$users = [
    ['id' => 1, 'name' => 'John', 'email' => 'john@example.com'],
    ['id' => 2, 'name' => 'Jane', 'email' => 'jane@example.com'],
    ['id' => 3, 'name' => 'Bob', 'email' => 'bob@example.com'],
];

$names = array_column($users, 'name');
// Result: ['John', 'Jane', 'Bob']

Extract IDs

$ids = array_column($users, 'id');
// Result: [1, 2, 3]

Using Index Key

Index by Another Column

$users = [
    ['id' => 1, 'name' => 'John'],
    ['id' => 2, 'name' => 'Jane'],
];

$indexed = array_column($users, 'name', 'id');
// Result: [1 => 'John', 2 => 'Jane']

Create Lookup Array

$products = [
    ['id' => 1, 'name' => 'Product A', 'price' => 100],
    ['id' => 2, 'name' => 'Product B', 'price' => 200],
];

$lookup = array_column($products, 'price', 'id');
// Result: [1 => 100, 2 => 200]
// Use: $lookup[1] to get price of product 1

Real-World Examples

Database Results

$results = [
    ['id' => 1, 'title' => 'Post 1'],
    ['id' => 2, 'title' => 'Post 2'],
];

$titles = array_column($results, 'title');
$ids = array_column($results, 'id');

Create Options Array

$categories = [
    ['id' => 1, 'name' => 'Tech'],
    ['id' => 2, 'name' => 'Design'],
];

$options = array_column($categories, 'name', 'id');
// Result: [1 => 'Tech', 2 => 'Design']
// Use in select dropdown

Conclusion

array_column() is essential for:

• Extracting columns from multi-dimensional arrays
• Transforming data structures
• Creating lookup arrays
• Working with database results

Key Points:

• Extracts single column
• Can index by another column
• Works with associative arrays
• Useful for data transformation

Mastering array_column() simplifies working with structured data in PHP.