ramsey / array_column Goto Github PK

Provides functionality for array_column() to projects using PHP earlier than version 5.5.

License: MIT License

PHP 100.00%

array_column's Introduction

array_column() for PHP

This simple library provides functionality for array_column() to versions of PHP earlier than 5.5. It mimics the functionality of the built-in function in every way.

Usage

array array_column(array $input, mixed $columnKey[, mixed $indexKey])

Given a multi-dimensional array of data, array_column() returns the values from a single column of the input array, identified by the $columnKey. Optionally, you may provide an $indexKey to index the values in the returned array by the values from the $indexKey column in the input array.

For example, using the following array of data, we tell array_column() to return an array of just the last names, indexed by their record IDs.

<?php
$records = array(
    array(
        'id' => 2135,
        'first_name' => 'John',
        'last_name' => 'Doe'
    ),
    array(
        'id' => 3245,
        'first_name' => 'Sally',
        'last_name' => 'Smith'
    ),
    array(
        'id' => 5342,
        'first_name' => 'Jane',
        'last_name' => 'Jones'
    ),
    array(
        'id' => 5623,
        'first_name' => 'Peter',
        'last_name' => 'Doe'
    )
);

$lastNames = array_column($records, 'last_name', 'id');

If we call print_r() on $lastNames, you'll see a resulting array that looks a bit like this:

Array
(
    [2135] => Doe
    [3245] => Smith
    [5342] => Jones
    [5623] => Doe
)

Installation

The easiest way to install this library is to use Composer:

php composer.phar require ramsey/array_column

Then, when you run composer install, everything will fall magically into place, and the array_column() function will be available to your project, as long as you are including Composer's autoloader.

However, you do not need Composer to use this library.

This library has no dependencies and should work on older versions of PHP. Download the code and include src/array_column.php in your project, and all should work fine.

When you are ready to run your project on PHP 5.5, everything should continue to run well without conflicts, even if this library remains included in your project.

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array_column's Issues

Not working on deeper arrays?

I'm trying to parse the following array **:

This array is contained in $data. Calling array_column($data,'id') returns an empty array:

Array
(
)

There are no errors, no warnings, no notices. Unless I'm doing something wrong, it would seem that there is some sort of limit on array depth?

Ideas? Particularly how to debug this?

** this is a standard datastructure from the Facebook API, turn into a PHP array by using json_decode($json, TRUE)

Recommended usage

I am currently working a on a project which is used on multiple servers with multiple PHP versions.

Until now I used put backport packages (like this) into require-dev (for testing) and support section of composer.json.

However recently I found out that I could even require it in all cases which has two effects:

it gets installed in case of every installation (every PHP version, this is not so good)
I don't have to manually install it based on the deployment environment

A third option is to install it globally on older servers, but I don't like that either.

Does anybody have a good answer for this? What is the best practice?

Support for objects?

It would be great if you could pass in an array of objects, and the index key provided merely accessed one of the properties to be used when re-indexing the array of objects.

I know that you can implement the ArrayAccess interface, but it's a bit tedious to do this for every object that you just want to be able to reindex an array of.

A simple check to see if $row is an object would be good. A more robust implementation might allow you to define a method call against a class as the index key e.g. array('Person', 'getID').

Of course this would make it inconsistent with the actual PHP implementation, but it would make this more useful. Having to implement ArrayAccess marginally defeats the purpose of using the terse syntax of array_column() over the slightly more verbose array_map()

Inconsistency with built-in array_column() when 3rd parameter element value is not string

Your array_column() is giving different results from PHP's built-in array_column() if the 3^rd parameter is not null and the element value is not a string. For example:

$records = array(
    array('id' => 2135, 'first_name' => 'John', 'last_name' => 'Doe'),
    array('id' => true, 'first_name' => 'Sally', 'last_name' => 'Smith'),
    array('id' => null, 'first_name' => 'Jane', 'last_name' => 'Jones'),
    array('id' => 56.23, 'first_name' => 'Peter', 'last_name' => 'Doe'),
);

PHP 5.6.3 array_column() gives:

Array
(
    [2135] => Doe
    [2136] => Smith
    [2137] => Jones
    [2138] => Doe
)

Your array_column() gives:

Array
(
    [2135] => Doe
    [1] => Smith
    [] => Jones
    [56.23] => Doe
)

i want to fetch one column from array.

this is my array and i want to fetch only the value of deviceToken ...

Return original index

It would be great if the function could return the original index of the row.

Example:

$array = array(
    'key' => array(
        'element' => 'value'
    )
);

// Returns array('key' => 'value')
array_column($array, 'element', true);

I know it only mimics the core function, but still would be a great feature.

Why do you use func_get_args?

Why not simply checking the parameters?

Unnecessary code

First of all - great job! 😉

Why do you need to check the count of the arguments at all? As I know, PHP will throw an error, if there are less parameters given than required, just don't allow the arguments be optional (as in the manual they are not)! This can be written like this:

<?php
// function array_column($input = null, $columnKey = null, $indexKey = null)
function array_column(array $input, $columnKey, $indexKey = null)
{
    // ...

    // !!! Now you can get rid of this code too:

    if ($argc < 2) {
            trigger_error("array_column() expects at least 2 parameters, {$argc} given", E_USER_WARNING);
            return null;
    }

    if (!is_array($params[0])) {
            trigger_error('array_column() expects parameter 1 to be array, ' . gettype($params[0]) . ' given', E_USER_WARNING);
            return null;
    }

    // ...
}

Ald also the

if (!is_array($params[0]))

will throw an error, if an empty array was given. In that case there should be an extra isset() checking.